Hi DamonHD,
Initially voltage drop was minuscule when cool, but now that they are baking outside in 95f/35c I am seeing approx. 1.5v drop off per panel. I have not measured the little panels in open air at the same temperature to know if this is normal, or an exception due the the acrylic picture frames holding more heat (which I bet they are).
As far as UV resistant, I don't know that either. The larger of the two panels in the photo I had in a single 3x5 acrylic frame for the last 2 years, but the wind had blown it around enough where it had fell off my deck rail several times and had broke a corner as well as added several cracks to the frame. It never yellowed, but did appear to become more brittle with use in the elements.
I think both panels are at least 4 to maybe 5 years old.
Best,