Heat Treatment of Glass

Toughening (T) is a heat treatment conducted on annealed glass and is also known as ‘Tempering’. The process is conducted using a furnace that can heat glass up to 700 degrees Celsius and then a quench process to cool the glass causing stress in the glass. The purpose is to strengthen the glass (up to 5x stronger than annealed glass) to make it more resistant to breakage, including Thermal Stress cracking. It also becomes Grade A safety when done by a certified processor as per AS 2208: Safety glazing materials in buildings.

Heat Strengthening (HS) is a heat treatment conducted on annealed glass similar to Toughening. The process is the same but not as intense as Toughening. The purpose is to strengthen the glass (up to 2x stronger than annealed glass) to make it more resistant to breakage, including Thermal Stress cracking. It is important to note that Heat Strengthened glass is not Grade A Safety glass but whenever Grade A safety is not required it is a more affordable option compared to a Toughening & Heat Soaking combination (see Heat Soaking section).

Download the Whitepaper for more information.