SFAIK, most acrylic/polycarbonate blocks out 97% of UV. Many optometrists have a UV checking instrument and I've seen demos where even plain, clear material working almost as well as tinted in terms of UV. I've flown hundreds of hours in full sunshine inside a slightly tinted glider glider canopy and can't say that I've had any noticeable skin colour change apart from when I take off my rose tinted sunnies.
Heat's another thing altogether and the heat goes straight through perspex. But in a sailplane, you need max vision and a sunshade is an absolute nono.
D
