When car companies run ads on television touting their vehicle's new safety features, they rarely mention the car's windshield or the surrounding windows, but the glass surrounding you in those vehicles has been designed and manufactured with your safety in mind. Although automotive glass looks the same as any other type of glass, it functions very differently.
In most homes, the windows in each room are made from a standard type of glass that will shatter into large shards when it breaks. With the exception of a sliding glass door or front door, these home windows don't receive the same amount of strain that an automotive window does. A car, on the other hand, will encounter many potholes, rocks and fender benders in its lifetime. Because of this, automotive glass is manufactured into two different types of safety glass to protect both the structure of the vehicle and the occupants inside. The first type of glass is called laminated glass, which is for the windshield. The second type of glass is known as tempered glass, which is used for the vehicle's side and back windows.
Laminated glass is a type of safety glass that holds together when shattered. In the event of breaking,it is held in place by an interlayer,typically of polyvinyl butyral (PVB) between its two or more layers of glass.The interlayer keeps the layers of glasses bonded even when broken and its high strength prevents the glass from breaking into large sharp pieces.This produces the characteristics “Spider Web” cracking pattern when the impact is not enough to completely pierce the glass.
Tempered glass is primarily used for side window glass and rear windshield glass. When it breaks, tempered glass shatters into small pieces rather than long sharp shards, thus protecting people from causing injuries. Its sturdy , thick and stable.
A defogger, demister, or defroster is a system to clear condensation and thaw frost from the windshield, backglass, or side windows of an automobile.
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