Polycarbonate is a type of plastic that is used in many kinds of industrial and manufacturing applications. The bulletproof windows that are attached to security vans and the compact discs (CDs) that hold music and video are all made from polycarbonate. One of the most important features of polycarbonate compared to other types of plastics is its strength coupled with very light weight. Acrylic may be 17 percent stronger than glass, but polycarbonate is almost unbreakable. This is the reason why polycarbonate is used in the enclosures that are a part of modern banks and the windows in drive through restaurants. Polycarbonate is also just a third of the weight of acrylic and a sixth of the weight of glass. The only disadvantage of polycarbonate over both acrylic and glass is that it is more expensive.
Polycarbonate is most recognizable to most people in the form of compact discs and DVDs. It is also seen by those who wear eyeglasses because the lenses of some are made from clear polycarbonate. Polycarbonate is actually a great material for making lenses because it is absolutely transparent and has a high infraction index, which means it can bend light at a greater degree compared to both glass or other plastics.
Polycarbonate lenses are also used in sunglasses, especially those that use filters in order to shield the eyes from ultraviolet and near-ultraviolet rays. These lenses are polarized in order to cut down on glare. The near indestructibility of polycarbonate is also why it is used in sports sunglasses.