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Glass is a non-crystalline material created naturally from volcanic magma. This glass is called obsidian and is usually black with impurities. It is said that if glass is left undistributed, can maintain indefinitely its overall form and amorphous microstructure at a temperature below its glass transition temperature. History speaks that manufacture of glass dates back to 3000 BC and nowadays glass technology is widely used in almost every household in the forms of objects such as bottles, mirrors, windows, bulbs etc. Specific chemical compositions with properties of glass such as refractive, reflective and transmission makes it suitable for technological applications such as optics and optoelectronics. With its versatile properties glass can be used as an art medium for display purposes. |
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Due to absence of electronic transition states in the range of visible light, it is transparent. It is transparent also due to increase homogeneity than the wavelength. This transparency property has led to manufacture of many glass objects such as drinking glasses, bowls, bottles, mirrors, light bulbs, windows etc. For the manufacture of laboratories, flasks, test tubes, lenses and other laboratory equipment borosilicate glass is normally used. For the most demanding applications, quartz glass is used. |
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Glass polymerization is a technique that can be used to incorporate additives that modify the properties of a glass that would otherwise be destroyed during high temperature preparation. Sol gel is a finest example of glass polymerization and enables the possibility of embedding active molecules, such as enzymes, to add a new level of functionality to glass vessels. Glass is commonly used in buildings as windows, internal glazed partitions and as architectural features. It is also used as a structural material in the form of beams and columns as well as in the form fins. Glass has a high theoretical yield stress; it is very susceptible to brittle failure and has a tendency to shatter upon. Other examples of glass in buildings include wired, heat strengthened and laminated glass. Glass fibre insulation is common in roofs and walls. Foamed glass, made from waste glass, can be used as lightweight, closed cell insulation. |
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Ordinary glass appears colorless to the naked eye but if added to it metals and metal oxides during its manufacture, the color can be change. Eg:
- Iron (II) oxide results in bluish green glass, frequently used for beer bottles, together with chromium gives a richer green color used for wine bottles.
- Sulphur, together with carbon and iron salts is used to form iron polysulphides and produce amber glass ranging from yellowish to almost black.
- Manganese can be added in small amounts to remove the green tint given by iron, or in higher concentrations to give glass an amethyst color. Manganese is one of the oldest glass additives, and purple manganese glass was used since early Egyptian history.
- Manganese dioxide, which is black, is used to remove the green colorfrom the glass in a very slow process that is converted to sodium permagnate, a dark purple compound.
We can find the most common techniques for producing glass art. These techniques include blowing, kin-casting, fusing, slumping, flame working, hot sculpting and cold working. Cold work futher included traditional stained glass work as well as other methods of shaping glass at room temperature. Glass can also be cut with a diamond saw or copper wheels embedded with abrasives and polished to give gleaming facets, the techniques used in creating Waterford crystal. |
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Objects made out of glass include, not only traditional objects such as vessels, bowls, vases, bottles and other containers, smoking pipes but an endless range of sculpture and installation art as well. Colored glass is often used, though sometimes the glass is painted. |
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