From Big Medical Encyclopedia

GLASS — the hard amorphous material which is characterized by fragility, transparency, resistance to chemical and thermal influences. Properties C. are defined by a combination of the components forming it and manufacturing techniques. Distinguish S. inorganic and organic. Inorganic S. is developed on the basis of silicon dioxide (silicate S.) and other oxides (phosphatic, borate, aluminophosphate S., etc.). Inclusion in S.'s structure of oxides of zinc, zirconium, titanium and some other elements increases its chemical stability and thermal stability; oxides of lead increase optical qualities of Page. Depending on the making components C. can be transparent or opaque, colourless or painted, passing or absorbing ultra-violet (see. Cathedral glass ) and infrared beams, as well as ionizing radiation. Organic S. — optically transparent hard materials on the basis of organic polymers; it has the increased durability, small weight, resistance to blows, does not give dangerous splinters.

To destination distinguish tare, construction (window, figured, glass blocks, fibreglasses, etc.), technical (quartz, lighting, glass fiber, etc.) and high-quality S. Naiboley quartz S. (one-component silicate) has high chemical stability, fire resistance and thermal stability; also the greatest svetopropuskaniye, especially ultraviolet rays is peculiar to it. It is used for production laboratory glassware (see), crucibles, optical devices, tanks for the medical, chemical, pharmaceutical and food industry. Besides, there is safe nonshattering S. for a glazing of vehicles; the fotokhromny S. changing a svetopropuskaniye depending on intensity of lighting; Page universal isolating (sun-protection, soundproofing, bulletproof), etc.

Transparency, chemical and thermal endurance allow to use widely S. in medicine — for production of ampoules, pharmaceutical and a lab. ware, points, thermometers, details of medical devices, objects of patient care. Good gigabyte. S.'s qualities are defined by the fact that it easily washes, will be sterilized, is the reliable screen for dust and microflora.

The page is widely used in construction (for a glazing of svetoproyem, the device of translucent barriers and partitions) and in life (glasswares, mirrors, details of furniture and lamps, art products, etc.) * Gigabyte. requirements to construction S. are defined by purpose of glass barriers to which production it is applied: it shall pass enough light, creating necessary conditions for visual contact, or on the contrary, to provide visual isolation, shall have sufficient heat-protective properties and it is easy to give in to cleaning. Glasswares shall be chemically stable (harmless), thermally steady, is deprived of the cutting sides and to have the surface convenient for cleaning and washing.

See also Glass industry .

Bibliography: Appen A. A. The chemistry flew down, L., 1974; Kachalov N. I. Glass, M., 1959; Inorganic materials with a variable svetopropuskaniye, under the editorship of V. F. Solinov, M., 1980; S.'s Nightingales of the Item and D and N of e e in and Yu. M. Steklo in architecture, M., 1981; Glass, under the editorship of H. M. Pavlushkina, M., 1973.

3. A. Skobareva.