# UV-Transparent Plastic?

I am looking for a type of plastic, preferably in the form of a sheet or film, that is weatherproof, durable, flexible, and both transparent and UV-transparent. Most films I've seen so far are treated to be UV-resistant, where can I find untreated plastics for purchase? Planning to use this plastic in order to cover a solar panel, without inhibiting energy output.

• The number of UV photons compared to those in the visible is very small, not only because of the black-body distribution from the sun but also because atmospheric ozone absorbs a lot of UV. So it may not be a cost effective solution since PMMA sheet is expensive. (They are treated to be UV resistant to extend their lifetime against UV induced photochemistry) – porphyrin Dec 6 '16 at 21:55

A 3 mm Plexiglas G UVT layer seems to have a transmittance > 80% at $\lambda = 300~\mathrm{nm}$ and above.