Toughened laminated glass is composed of at least two panes of tempered glass by PVB or SGP film. It has a much higher thermal shock resistance than float laminated glass.
When the pane breaks, the small fragments with blunt edges generally remain stuck to the PVB or SGP film. It is difficult to pierce the film, which considerably reduce the risk of injury.
Toughened Laminated Glass With Holes & Polished Edges
SGP Edge
Heat Soaked Testing
A rare but nonetheless undesirable property of tempered glass is spontaneous breakage: tiny inclusions of nickel sulfide, invisible to the naked eye, expand in volume over time, and can cause the pane to break unexpectedly even years after installation. One reliable means of detecting nickel sulfide inclusions is the heat soaked test, in which the panes are warmed to about 290℃. During a soak time of about four hours in the heat soak oven, the tempered glass panes will nickel sulfide inclusion will probably break and hence never be installed in the first place.