Heat-treated glass is produced by transporting annealed glass through a tempering oven, heated to an approximate temperature of 1,150 fahrenheit. The glass is then rapidly cooled by blowing air evenly on both sides of the glass. This is called the quenching process, which is performed before the glass is removed from the tempering line. The cooling process places the surface of the glass into a state of high compression and the core of the glass in compensating tension.
