Glass that has been heat treated to induce surface compression in order to add strength. On breaking, it breaks into sharp pieces, but smaller than pieces of broken annealed glass. It does not dice, as does tempered glass on breaking. It is intermediate in strength between annealed glass and toughened glass. It is used in the curtain wall design as spandrel glazing of multistoried buildings. It is usually polished plate glass or patterned glass on one surface of which is fused a colored enamel.
