Plexiglas is a trade name for "Polymethyl methacrylate" It is not glass at all, but actually transparent plastic.
The material was first created in 1843. Several different chemists experimented with it during the late 1800s.
The name "PLEXIGLAS" was created in 1933 by German scientist Otto Rohm. This new variation quickly proved to be very reliable.
Plexiglas was used on a large scale during World War II. It quickly found its way into bomber cockpits, gun turrets and submarine periscopes.
Plexiglas is now used around the world. It can be used in place of glass, and is used in everything from airplanes to automobiles.