Last Updated: Mar 09, 2018 Views: 3
Kitchen table top glass is usually tempered or strengthened glass. Tempered glass is preferred over regular annealed glass for its extra strength and resistance to breakage. Glass can be thermally toughened by being suspended or placed into equipment where it is quickly heated to about 150 Celsius above the transformation temperature, as soon as the glass as taken away from the furnace it is chilled with a blast of cold air from a system with cold air jets. The rapid cooling freezes the glass surface and leaves the inside warmer so the outer layer is subjected to compression and the inner layer is tension. The finished product is a finished layer of safety glass( Schott guide to glass p 77).
Chemically toughened glass is based on ion exchange. In 1891 Otto Schott developed a very strong glass by coating glass with high thermal expansion with a glass of low expansion. Chemically toughened glass is used today widely in the production of tableware and flashed opal glass (Schott guide to glass p 78).
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