What is the process used to produce glass that makes it 3 to 5 times stronger?

Tempering is a heat treatment process applied to glass that significantly increases its strength. When glass is tempered, it is first heated to a temperature of around 1,320°F (about 700°C) and then rapidly cooled. This cooling creates compressive stress on the surface, which makes the glass more resistant to impacts and thermal shock compared to standard glass.

The process results in glass that can withstand greater forces without breaking, achieving strength levels that are 3 to 5 times greater than non-tempered glass. It also ensures that if tempered glass does break, it shatters into small, blunt pieces instead of sharp shards, reducing the risk of injury.

Other processes such as annealing, laminating, and coating serve different purposes. Annealing is a process used to relieve internal stresses in glass, resulting in a more uniform product but does not significantly increase strength. Laminating involves sandwiching a layer of plastic between two sheets of glass for added safety and sound insulation but does not inherently increase glass strength. Coating applies a layer on the glass for purposes like UV protection or glare reduction, but it does not change the material's inherent strength characteristics. Thus, tempering is specifically the process that enhances the glass's strength to the levels specified