Laminated safety glass, or as it is more commonly known, bullet proof glass, is basically two pieces of glass, with a PVB (polyvinyl butyral) film sandwiched in between. It is a type of safety glass that can still hold together, in the event of breaking.
Laminated safety glass is processed by pressing PVB film in between the two glass panels and allowing it to bond through heat and pressure. In the event of something hitting the glass, the PVB film absorbs the impact and helps keep the pieces of glass bonded together, preventing smaller glass pieces to break away and shatter. Multiple pieces of glass and thicker PVB films increase the strength of laminated safety glass. For this reason, laminated safety glass is usually used in instances where there is a big possibility of big impacts that can cause the glass to break and shatter.
Laminated safety glass can be composed of more than two pieces of glass with varying thickness and color, making it not only safe but aesthetically pleasing as well. Similar to the glass, different types of PVB film can be used in between.