Glass making, one of the oldest of industries, has had a fascination for man throughout the ages. The transmutation of common sand and earth into a gem- like, rigid, transparent material has all the romance of alchemy. Today, by far the greater volume of glass is made by fully automatic means, and a visit to a modern bottle factory, The glass technologist is the alchemist behind the scenes who must daily exercise his art, assisted by science, to ensure that the machines are capable of functioning properly. Glass cannot be shaped by brute force alone, as is the case with metals or plastics; it must be persuaded into shape by encouragement or constraint so that, like a perverse mule, its movement complies with its own inclination and yet is in the right direction. Therefore all amorphous materials are not necessarily glasses. The products obtained in all these processes give rise to X-ray diffraction patterns, which lack crystalline features such as sharp diffraction peaks. Their electron diffraction patterns generally consist of one or two diffuse hallows. But many such amorphous materials do not exhibit glass transition. Therefore it is assumed, unless stated otherwise, that glasses are only those amorphous solids which are obtained by the super cooling of melts. When a liquid is cooled from a high temperature to its melting temperature, (Tm), it generally solidifies to a crystalline product. It is only rarely that melts do not crystallize when they are cooled slowly. Therefore in order to obtain a glass the rate of super cooling has to be such that crystallization is bypassed. This requires rapid quenching in order to bypass crystallization. Thus the cooling or quenching rate, Q, which is a kinetic parameter is of great significance for glass formation. While in connection with annealing the residual stress in the glass was high if the holding temperature was high and the subsequent cooling rapid. Thermal toughening exploits this situation to the full. The holding temperature is made as high as the glass will stand without sagging and the cooling rate made as rapid as the glass will stand without breaking under the temporary chilling stress. Infact, the sagging temperature is slightly exceeded and the ware usually shows sign pf distortion tong marks. ? USES & APPLICATION A fully tempered glass is used in most modern glass facade, where glass strength is required. A fully tempered glass is recommended for windows that are on high floors or skylights where people are required to stand on top for cleaning. Tempered glass is also used in areas where risk of thermal breakage or impact breakage is high, fully tempered glass should be used so as to avoid risk of injury. Glass strength is also required in point fixed glazing, bolted and patches fittings. Toughened glass is used when strength, thermal resistance and safety are important considerations. The most commonly encountered tempered glass is that used for side and rear windows in automobiles. Fully tempered glass is used traditionally in place of other glass products in applications requiring increased strength and reduced likelihood of injury in the event of breakage. The building industry, motor vehicle industry and certain manufacturing industries find tempered glass is effective and economical in a wide range of applications. Fully tempered glass can satisfy federal, state and local building code requirements for safety glazing in such applications as doors, side lights, shower and tub enclosure, and interior partitions. It is also used in storm doors, patio-door assemblies, and escalator and stairway balustrades. As a glazing product it is used in windows and in spandrel areas (for wind pressure, small missile impact and thermal stress resistance). Special building applications include sloped glazing, racquetball courts, skylights (see below), and solar panels. Any conditions or requirements imposed in the applicable safety glazing laws and building codes limiting such special uses should be determined prior to glazing. MARKET SURVEY The glass industry represents a number of definable product segments: (a) flat glass including Float Glass, (b) glass containers and hollowware, (c) vacuum glass, (d) domestic and industrial glassware, (e) crystal glass, (f) fibreglass, (g) glass wool, (h) TV picture tube glass shells, and (i) laboratory glass. Most of the glass products have both industrial and consumer usages. Laboratory glass is a minor constituent. So are fibreglass and glasswool - although fibreglass is gaining momen-tum increasingly. The industry is growing at around 8% per annum. Consumption per capita of glass in India is only about 0.8 kg compared to 3.5 kg in China, 5.2 kg in Thailand, 12 kg in Malaysia and 2.5 kg in Indonesia. The total organised producers in the glass market have a turnover estimated at over Rs 40 bn, represented by a fairly large number of suppliers. The dominance of China as a major market supplier of glass products has been increasing with economic liberalisation and rising foreign investment. China accounts for about one-third share in the worldwide demand of flat glass. India has one of the lowest per capita flat glass consumption but with rapid growth in domestic construction and automotive market, it presents a significant opportunity for global majors, which have entered the market in a big way. India exports about 13,000 tonne of glass per month to the Middle East, African countries, Europe and South America. The rapid increase in the demand for flat glass in the domestic market has resulted in a cutback in exports by as much as 60% in the last couple of years. The two main entrants in the glass industry in the recent years have been Float Glass (a technological variant of flat or sheet glass) and crystalware. Fibreglass and glass wool are still a small turnover industry but has been operating in India for quite sometime. Flat glass is segmented into conventional sheet glass and Float Glass. Float Glass is stronger (by 25%) than normal sheet glass. It also has a much higher degree of optical clarity. Other varieties include figured and wired glass. PRESENT MANUFACTURERS Asahi India Glass Ltd. Atul Glass Inds. Ltd. Auroplast India Ltd. Gold Plus Glasses India Ltd. Hindusthan Safety Glass Works Pvt. Ltd. Saint-Gobain Sekurit India Ltd.