How bulletproof glass works?

‘Bulletproof’ glass is very different to ordinary glass. It can be more correctly called bullet-resistant glass because no glass is totally bulletproof. It’s made from multiple layers of tough glass with inter layers of various plastics.

Sometimes, there’s a final inner layer of polycarbonate (a tough type of plastic) or plastic film to prevent spalling (where dangerous shards of glass or plastic splinter off following the impact of a bullet).

This sandwich of layers is called a laminate. It can be up to ten times thicker than a single pane of ordinary glass and it’s usually very heavy.When a bullet strikes bulletproof glass, its energy spreads out sideways through the layers. Because the energy is divided between a number of different pieces of glass and plastic, and spread over a large area, it is quickly absorbed.

The bullet slows down so much that it no longer has enough energy to pierce through — or to do much damage if it does so. Although the glass panes do break, the plastic layers stop them flying apart.