Bullet-resistant glass is a strong but optically transparent material that is cannot be penetrated when struck. However, they are not completely impenetrable.

– Glass is brittle and it does not have a good orderly crystalline structure. If it did, it would be like metal steel, where it dents and deforms instead of shattering.

– This allows the glass to absorb the bullet’s energy by transferring the kinetic energy of the bullet into shattering the glass.

– The softer plastic layer reinforces the glass by holding it in place and allowing the glass to flex back as it absorbs the impact.

– The polycarbonate and laminate also spread the force of the bullet laterally across the entire glass surface.

– Layering these in multiple sheets allows the window to use properties of both materials more effectively; such as the glass on the backside shattering while the undamaged glass holds together the window. This also allows the glass to stop more that one bullet.

– Since polycarbonate is very strong and does not shatter like glass it is an excellent candidate for bullet-proofing.