Excellent observation on the aircraft windows. Remember that the outer window of Boeing and Airbus planes commonly found flying around the USA start out life as highly crosslinked Cast Acrylic
in excess of two inches thick. The lenses are then fixtured into a large hydraulic apparatus that when subject to the glass transition temperature for cast acrylic"stretches" the sheet to the correct mil spec thickness. The widows are then machined to size and annealed. The combination of the stretching and the annealing makes one tough sheet.
For the purposes of this forum the Aircraft material while acrylic
, would far exceed the budget
for portlight glazing. (Outer window only, the widow system contains three pcs.... acrylic outside, intermediate either AC or PC and an interior
pc normally ar coated Polycarb)
The extra strength imparted by the crosslinking, stretching and anealing make the sheet far more chemical resistant than the standard acrylic avalible to the marine
industry. The suppliers approved to provide this raw material to the strechers are Polycast, CYRO/ Degussa/Evonik, and to a lesser extent Mistubishi.
As an NMMA approved processor of acrylic products for the marine
industry I would advise against using windex or any product with petroluem distallates listed on the label. Caveat emptor.
UV resistance is a tricky one. None of the manufacturers warrenty their products against UV degridation but Evonik does have a 10 year warrenty against yellowing/ fading. It is my experience that a good quality domestically produced cast acrylic sheet (low residual monomer with low fabrication stress) will last in excess of 10 years. I have seen some go 25+. Watch out for the no name special acrylics dusted off from under the couter at your local glass shop.
Ultra Violet exposure and incompatible sealants are the enemy. Make sure your sealants are compatable with the lenses (check, check, check) and cover your acrylics when not in use.
Nice portlight istallation too...
Tony "Hatchmater" D'Andrea