The kids and I made some glow in the dark bracelets by welding bits of clear, glow, and black urethane together. I've worn one ever since, it's amazing how bright it glows with just a little exposure to the sun - or any strong source of UV.
Created once by accident in the factory - it was a complete accident with, apparently, the right mixture of clear urethane and a tiny amount of graphite powder. We were never able to reproduce it after trying many times but it really was an odd metallic reflctive silvery chrome looking thing. We only had a couple of inches of it.