Donate a Helmet, Plastic or Fiberglass for Testing

I had a wondering, if plastic Motorcycle Helmets are better or worse than Fiberglass Motorcycle helmets. My thinking is fiberglass is the better way to go. UV rays really work on plastic/polycarbonate plus I think the oils in plastic leach out over time making a polycarbonate brittle. Sure, new plastic on car fenders will bounce back after a bump up but wait a couple years and that same fender will crack and shatter as they flex less with age. Hard Plastic would seem to concentrate the impact in one area which would transfer to the head more. Of course liner padding should be considered I guess in both helmets.
Fiberglass will tend to crack at point of impact but like a Corvette body, transfers the shock all around the surface of the helmet taking and transferring and dissipating the force lessening the impact from one centralised location. Plus the glass fibers will hold the helmet together during impact and not shatter apart. A fiberglass helmet could be repaired and the repaired section would actually then be stronger.
I'd like to perform some tests but need helmets of different MFG's so if you have one to donate I'll document the tests and results here. I'd like both DOT approved and non approved helmets to see which is safer. So you have the "Why" of it.

I also have an idea for helmet liners that make fitting the individuals head much better and secure plus safer for the rider. Just need funding for prototype on that one though. The helmet shell tests I can do with no funding at all.