Toughened glass, also known as tempered glass after its method of production, is a type of safety glass that is five times stronger than annealed and laminated glass of the same size and thickness. 

Toughened glass gets this strength from the tempering process which sees it subjected to intense heating followed by rapid cooling during manufacture. This toughness gives tempered glass a far higher load and breakage resistance. Toughened glass needs to be hit a lot harder than other safety glass in order to break.

Whereas laminated glass holds in place when shattered, toughened glass breaks up into hundreds of tiny pieces. You will probably have seen this on the floor where a telephone box or bus stop had been vandalised. This method of breaking lowers the risk of injury compared to annealed glass which breaks up into larger, jagged pieces more likely to injure anybody in close proximity.

Tempered glass has a heat resistance four to five times stronger than standard glass and can withstand high temperature changes up to 250°C.