In article ,
"Peter Dohm" wrote:


I had simply presumed that all polycarbonate was nearly opaque to UV,
that
acrylic was not, and that neither had much affect on IR; but there now
appears to be a lot more to the story. I now suppose that you may be
guessing exactly right that something is added to filter UV--and it
could
very well be throughout the material or as a coating. In addition,
polycarbonate was previously notorious for its poor abrasion resistance,
and
its inability to be repolished; but the new formulations and/or coatings
have drastically improved the durability.

I have a pair of glasses that darken (don't remember what they are called)
that are safety glass rated, and have an anti scratch coating applied,
also.
They filter UV and have proven to be more scratch resistant by a couple
levels of magnitude better than any others I have ever had.

Could it be that they finally figured out how to make a good scratch
resistant coating? I don't know the answer, but they are far better than
the other coatings I have gotten in the past. Nice, too, that they came
from Wally World, so the price was right.
--
Jim in NC


I don't know, but it's very possible.

Although mine don't change color, the scratch resistant coating has been
remarkably effective. There are no discernable scratches after a couple of
years--despite treating them as though they were glass.

I hope that something as sturdy turns out to be available for canopies and
windows.

Peter

Plexiglass II UVA has been around for decades! It filters out UV A, but
I don't know about UV B. It is the stuff from which aircraft canopies,
windows, windshields, etc. have been made for at least the past 45 years.