Originally Posted by dwightdi
True Plexiglas is a tradmark from Rohm and Haas. It has been used for years in green houses and has excellent UV resistance. Some people sell Polystyrene and mistakenly call it Plexiglass. It will not hold up to UV. It will turn yellow and is quite brittle. Some people are selling rigid PVC and mislabeling it. It also has poor UV resistance and will turn brown. Aftrer it starts to turn brown it is very brittle. Lexan is a GE trade name for plycarbonate. There is a special grade for outdoor exposure and is quite good and far more impact resistant than any other material. All plastics are lighter than glass and you will find they open differently. They are also less rigid and therefore the window will bend more. They are also less scratch resistant so be careful how you clean them. I do not know what Andy is refering to but it is certainly not Plexiglas.
Plexiglass as refered to by Home Depot and Lowes, as well as many other suppliers.
Granted, it is cheap, but it does not offer any UV protection.
Accordingly, it cracks and crazes in 60 to 90, when exposed to the sun.
Through the years, I have replace several hundred "plexiglass" windows, with superior products, using the original glass, acrylite or Lexan.