Glass is an amorphous An "amorphous solid" is a solid in which there is no long-range order of the positions of the atoms. . Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous solid, many polymers (such as polystyrene) are amorphous, and even foods such as cotton candy are amorphous (non-crystalline A crystal or crystalline solid is a solid material, whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography. The process of crystal formation via mechanisms of crystal growth is called) solid Solid is one of the major states of matter. It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a gas does. The atoms in a solid are tightly bound to each other, material. Glasses are typically brittle A material is brittle if it is liable to fracture when subjected to stress. That is, it has little tendency to deform before fracture. This fracture absorbs relatively little energy, even in materials of high strength, and usually makes a snapping sound, and often optically transparent In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency (also called translucence or translucidity) only allows light to pass through diffusely. The opposite property is opacity. Transparent materials are clear, while translucent ones cannot be seen through clearly. Glass is commonly used for windows A window is a transparent opening in a wall or door that allows the passage of light and, if not closed or sealed, air and sound. Windows are usually glazed or covered in some other transparent or translucent material like a float glass. Windows are held in place by frames, which prevent them from collapsing in. Many glazed windows may be opened,, bottles A glass bottle is a bottle created from glass. Glass bottles can vary in size considerably, but are most commonly found in sizes ranging between about 10ml and 5 litres, and eyewear; examples of glassy materials include soda-lime glass Soda-lime glass, also called soda-lime-silica glass, is the most prevalent type of glass, used for windowpanes, and glass containers for beverages, food, and some commodity items. Glass bakeware is often made of tempered soda-lime glass, borosilicate glass Borosilicate glass is a type of glass with the main glass-forming constituents silica and boron oxide. Borosilicate glasses are known for having very low coefficients of thermal expansion , making them resistant to thermal shock, more so than any other common glass, acrylic glass Chemically, it is the synthetic polymer of methyl methacrylate. It is sold under many trade names, including Policril, Plexiglas, Gavrieli, Vitroflex, Limacryl, R-Cast, Per-Clax, Perspex, Plazcryl, Acrylex, Acrylite, Acrylplast, Altuglas, Polycast, Oroglass, Optix and Lucite and is commonly called acrylic glass, simply acrylic, perspex or, sugar glass Sugar glass is a brittle transparent form of sugar. It is prepared by heating sugar to at least the "hard crack" stage in the candy making process. Water is sometimes used in preparation, but it boils off in the finished product. Corn syrup is sometimes used to prevent the sugar from recrystallizing. Sugar glass is used in stunt, Muscovy-glass Muscovite is a phyllosilicate mineral of aluminium and potassium with formula K , and aluminium oxynitride Aluminium oxynitride is a transparent ceramic composed of aluminium, oxygen and nitrogen. It is marketed under the name ALON and described in U.S. Patent 4,520,116. The material remains solid up to 1,200 °C (2,190 °F), and is harder than glass. When formed and polished as a window, the material currently (2005) costs about US$10 to US$15 per. The term glass developed in the late Roman Empire The Roman Empire was the post-Republican phase of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean. The term is used to describe the Roman state during and after the time of the first emperor, Augustus. It was in the Roman glassmaking Despite the growth of glass working in the Hellenistic World and the growing place of glass in material culture, at the beginning of the first century AD there was still no Latin word for it in the Roman World. However, glass was being produced in Roman contexts using primarily Hellenistic techniques and styles by the late Republican period. The center at Trier Trier is a city in Germany on the banks of the Moselle River. It is the oldest city in Germany, founded in or before 16 BC, now in modern Germany A region named Germania, inhabited by several Germanic peoples, has been known and documented before AD 100. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire, which lasted until 1806. During the 16th century, northern Germany became the centre of the Protestant Reformation. As a modern nation-state,, that the late-Latin term glesum originated, probably from a Germanic The Germanic languages are a group of related languages that constitute a branch of the Indo-European language family. The common ancestor of all the languages in this branch is Proto-Germanic, spoken in approximately the mid-1st millennium BC in Iron Age northern Europe. Proto-Germanic, along with all of its descendants, is characterized by a word for a transparent In the field of optics, transparency is the physical property of allowing light to pass through a material; translucency (also called translucence or translucidity) only allows light to pass through diffusely. The opposite property is opacity. Transparent materials are clear, while translucent ones cannot be seen through clearly, lustrous Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. For example, a diamond is said to have an adamantine lustre and pyrite is said to have a metallic lustre. The term is also used to describe other items with a particular sheen (for example, fabric, especially silk and satin, or metals) substance.[1]
Strictly speaking, a glass is defined as an inorganic product of fusion which has been cooled through its glass transition Glass transition or vitrification refers to the transformation of a glass-forming liquid into a glass, which usually occurs upon rapid cooling. It is a dynamic phenomenon occurring between two distinct states of matter , each with different physical properties. Upon cooling through the temperature range of glass transition (a "glass to the solid state without crystallising.[2][3][4][5][6] Many glasses contain silica The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with a chemical formula of Si as their main component and glass former.[7] The term "glass" is, however, often extended to all amorphous solids An "amorphous solid" is a solid in which there is no long-range order of the positions of the atoms. . Most classes of solid materials can be found or prepared in an amorphous form. For instance, common window glass is an amorphous solid, many polymers (such as polystyrene) are amorphous, and even foods such as cotton candy are amorphous (and melts Melt is the term used to describe the working material in the steelmaking process, in making glass, and when forming thermoplastics. For thermoplastics, the term specifically refers to the plastic in its forming temperature, which can vary depending on how it is being used. For steelmaking, it refers to steel in liquid form that easily form amorphous solids), including plastics A plastic material is any of a wide range of synthetic or semi-synthetic organic amorphous solids[citation needed] used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic, resins Resin is a hydrocarbon secretion of many plants, particularly coniferous trees. It is valued for its chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials for organic synthesis; and as constituents of incense and perfume. In perfumery such products, or other silica-free amorphous solids. In addition, besides traditional melting Glass production comprehends two types of glass: sheet glass, made by the float glass process, and (ii) glass-container glass techniques, any other means of preparation are considered, such as ion implantation Ion implantation is a materials engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid. Ion implantation is used in semiconductor device fabrication and in metal finishing, as well as various applications in materials science research. The ions introduce both a, and the sol-gel The sol-gel process, also known as chemical solution deposition, is a wet-chemical technique widely used in the fields of materials science and ceramic engineering. Such methods are used primarily for the fabrication of materials starting from a chemical solution (or sol ) which acts as the precursor for an integrated network (or gel ) of either method.[7] Commonly, and physics The physics of glass is the science of the glassy or amorphous state of matter as seen from an atomic or molecular point of view. This article provides an overview of research into glass: a solid in which no significant crystallization has occurred. Thus there is no long-range ordering or extended formation of any Bravais lattice deal only with inorganic Traditionally, inorganic compounds are considered to be of a mineral, not biological origin. Complementarily, most organic compounds are traditionally viewed as being of biological origin. Over the past century, the precise classification of inorganic vs organic compounds has become less important to scientists, primarily because the majority of amorphous solids, while plastics and similar organics are covered by polymer science Polymer science or macromolecular science is the subfield of materials science concerned with polymers, primarily synthetic polymers such as plastics. The field of polymer science includes researchers in multiple disciplines including chemistry, physics, and engineering, biology Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy and further scientific disciplines.
Glass plays an essential role in science and industry. The optical and physical properties A physical property is any measurable property the value of which describes a physical system's state at any given moment in time. For that reason the changes in the physical properties of a system can be used to describe its transformations of glass make it suitable for applications such as flat glass Flat glass, sheet glass, or plate glass is a type of glass, initially produced in plane form, commonly used for windows, glass doors, transparent walls, and windshields. For modern architectural and automotive applications, the flat glass is sometimes bent after production of the plane sheet. Flat glass stands in contrast to container glass and, container glass Container glass is a type of glass for the production of glass containers, such as bottles, jars, drinkware, and bowls. Container glass stands in contrast to flat glass and fiberglass (used for thermal insulation and optical communication). Most container glass is soda-lime glass, produced by blowing and pressing techniques, while some laboratory, optics Optics is the branch of physics which studies the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Because light is an electromagnetic wave, other forms of electromagnetic radiation and optoelectronics Optoelectronics is the study and application of electronic devices that source, detect and control light, usually considered a sub-field of photonics. In this context, light often includes invisible forms of radiation such as gamma rays, X-rays, ultraviolet and infrared, in addition to visible light. Optoelectronic devices are electrical-to- material, laboratory equipment Laboratory equipment refers to the various tools and equipment used by scientists working in a laboratory. These include tools such as Bunsen burners, and microscopes as well as specialty equipment such as operant conditioning chambers, spectrophotometers and calorimeters. Another important type of laboratory equipment is Laboratory glassware, thermal insulator (glass wool Glass wool is an insulating material, made from fibre glass, arranged into a texture similar to wool. Glass wool is produced in rolls or in slabs, with different thermal and mechanical properties), reinforcement fiber (glass-reinforced plastic Glass-reinforced plastic or GRP is a composite material made of a plastic matrix reinforced by fine fibers made of glass. It is also known as GFK , or simply by the name of the reinforcing fibers themselves: fiberglass, glass fiber reinforced concrete Glass Fiber Reinforced Concrete is a type of fiber reinforced concrete. Glass fiber concretes are mainly used in exterior building façade panels and as architectural precast concrete. This material is very good in making shapes on the front of any building and it is less dense than steel), and art Glass art takes many forms. The glass may be crystal clear, colored or opaque. Glass may comprise all of the piece, or only be the predominant component. A glass art piece may be exhibited for its own sake, or have some limited utility in itself. Glass as a material is well suited to form works of art because of its pleasing appearance, durability,.
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History
Main article: History of glassThe history of creating glass can be traced back to 3500 BCE in Mesopotamia Mesopotamia is a toponym for the area of the Tigris-Euphrates river system, largely corresponding to modern-day Iraq, as well as some parts of northeastern Syria, southeastern Turkey, and southwestern Iran.
Glass production
Main articles: Glass production Glass production comprehends two types of glass: sheet glass, made by the float glass process, and (ii) glass-container glass and Float glass Float glass is a sheet of glass made by floating molten glass on a bed of molten metal, typically tin, although lead and various low melting point alloys were used in the past. This method gives the sheet uniform thickness and very flat surfaces. Modern windows are made from float glass. Most float glass is soda-lime glass, but relatively minorGlass ingredients
Quartz sand Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica , usually in the form of quartz (silica) as main raw material for commercial glass production Oldest mouth-blown window-glass in Sweden Sweden (pronounced /ˈswiːdən/ SWEE-dən, Swedish: Sverige pronounced [ˈsveːrijə] ( listen)), officially the Kingdom of Sweden (Swedish: Konungariket Sverige (help·info)), is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden has land borders with Norway to the west and Finland to the northeast, and water borders with (Kosta Glasbruk Kosta Glasbruk is a Swedish glassworks founded by two foreign officers in Charles XII's army, Anders Koskull and Georg Bogislaus Stael von Holstein, in 1742 . It is located in Kosta (between the cities of Kalmar and Växjö) in the forested Småland province. The surrounding region has become known as the "Kingdom of Crystal" and is now, Småland Småland (Smolandia) is a historical province (landskap) in southern Sweden. Småland borders Blekinge, Scania or Skåne, Halland, Västergötland, Östergötland and the island Öland in the Baltic Sea. The name Småland literally means Small lands. The latinized form Smolandia has been used in other languages. The highest summit in Småland is, 1742). In the middle is the mark from the glassblower's pipe.Pure silica (SiO2) has a "glass melting point"—at a viscosity of 10 Pa·s (100 P)—of over 2300 °C (4200 °F). While pure silica can be made into glass for special applications (see fused quartz), other substances are added to common glass to simplify processing. One is sodium carbonate (Na2CO3), which lowers the melting point to about 1500 °C (2700 °F) in soda-lime glass; "soda" refers to the original source of sodium carbonate in the soda ash obtained from certain plants. However, the soda makes the glass water soluble, which is usually undesirable, so lime (calcium oxide (CaO), generally obtained from limestone), some magnesium oxide (MgO) and aluminium oxide (Al2O3) are added to provide for a better chemical durability. The resulting glass contains about 70 to 74% silica by weight and is called a soda-lime glass.[8] Soda-lime glasses account for about 90% of manufactured glass.
Most common glass has other ingredients added to change its properties. Lead glass or flint glass, is more 'brilliant' because the increased refractive index causes noticeably more "sparkles", while boron may be added to change the thermal and electrical properties, as in Pyrex. Adding barium also increases the refractive index. Thorium oxide gives glass a high refractive index and low dispersion and was formerly used in producing high-quality lenses, but due to its radioactivity has been replaced by lanthanum oxide in modern eye glasses. Large amounts of iron are used in glass that absorbs infrared energy, such as heat absorbing filters for movie projectors, while cerium(IV) oxide can be used for glass that absorbs UV wavelengths.
Another common glass ingredient is "cullet" (recycled glass). The recycled glass saves on raw materials and energy. However, impurities in the cullet can lead to product and equipment failure.
Finally, fining agents such as sodium sulfate, sodium chloride, or antimony oxide are added to reduce the bubble content in the glass.[8] Glass batch calculation is the method by which the correct raw material mixture is determined to achieve the desired glass composition.
Composition and properties
There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly crosslinked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb4+ replacing Si4+), or as a modifier.
The presence of non-bridging oxygens lowers the relative number of strong bonds in the material and disrupts the network, decreasing the viscosity of the melt and lowering the melting temperature.
The alkaline metal ions are small and mobile; their presence in glass allows a degree of electrical conductivity, especially in molten state or at high temperature. Their mobility however decreases the chemical resistance of the glass, allowing leaching by water and facilitating corrosion. Alkaline earth ions, with their two positive charges and requirement for two non-bridging oxygen ions to compensate for their charge, are much less mobile themselves and also hinder diffusion of other ions, especially the alkalis. The most common commercial glasses contain both alkali and alkaline earth ions (usually sodium and calcium), for easier processing and satisfying corrosion resistance.[9] Corrosion resistance of glass can be achieved by dealkalization, removal of the alkali ions from the glass surface by reaction with e.g. sulfur or fluorine compounds. Presence of alkaline metal ions has also detrimental effect to the loss tangent of the glass, and to its electrical resistance; glasses for electronics (sealing, vacuum tubes, lamps...) have to take this in account.
Addition of lead(II) oxide lowers melting point, lowers viscosity of the melt, and increases refractive index. Lead oxide also facilitates solubility of other metal oxides and therefore is used in colored glasses. The viscosity decrease of lead glass melt is very significant (roughly 100 times in comparison with soda glasses); this allows easier removal of bubbles and working at lower temperatures, hence its frequent use as an additive in vitreous enamels and glass solders. The high ionic radius of the Pb2+ ion renders it highly immobile in the matrix and hinders the movement of other ions; lead glasses therefore have high electrical resistance, about two orders of magnitude higher than soda-lime glass (108.5 vs 106.5 Ohm·cm, DC at 250 °C). For more details, see lead glass.[10]
Addition of fluorine lowers the dielectric constant of glass. Fluorine is highly electronegative and attracts the electrons in the lattice, lowering the polarizability of the material. Such silicon dioxide-fluoride is used in manufacture of integrated circuits as an insulator. High levels of fluorine doping lead to formation of volatile SiF2O and such glass is then thermally unstable. Stable layers were achieed with dielectric constant down to about 3.5–3.7.[11]
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Tue, 15 Jun 2010 19:08:31 GMT+00:00
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john
Wed, 01 Sep 2010 19:04:54 GM
Alice Through The Looking . Glass. Retold For Younger Readers From The Story By Lewis Carroll. Published By Hampster Books In Circa 1930 s Hardback. This scarce hardback book of 78 pages has nice clean pages, tight binding and no ...
Q. What is the difference between frosted glass and sand-blasted glass? Anybody can help me? It is very importmant for me. Thank you so much.
Asked by vantulips - Tue Nov 27 07:20:17 2007 - - 5 Answers - 1 Comments
A. Acid-etched frosted glass is more commonly used to make glass with more intricate designs. Sandblasting is used when the frosting is for a large pane of glass. Sandblasted frosted glass can also have some designs by using tape or another material to block the sand, but those designs are usually more simple.
Answered by Keelan C - Wed Nov 28 22:37:29 2007
