Carnival Plastics in New York, in the 1950's, made (or bought from Rosbro) a line of really cute slightly fat, figural ornaments in the shape of animals.  They featured circus animals as well as regular ones (dogs, cats), and one of their biggest sellers were the "glow in the dark".  They did make these ornaments in regular styrene (hard plastic) in colors, but it was the glow in the dark ornaments that caught on and were their biggest sellers.  The ornaments were treated with chemicals to create their florescence.  Unfortunately, over time, that chemical breaks down, and the florescence pretty much dies out.  They will glow - a bit, for a very short while, after exposure to a really bright light. Sunlight doesn't do it, but a super bright flashlight does. I have bought the glow in the darks by a variety of manufacturers (always the vintage ones), from a variety fo dealers, and it's the same result.  So, they are adorable, and really special vintage ornaments, but please don't expect a lot of "glow".  Anyway, this fellow has no damage, and his paint is good!  He is about 4" tall, and still has his hook for hanging from the tree.  BTW, I recommend that you not use a metal hook to hang him from your tree - use a ribbon or string, as the metal will react with the plastic over time, and the hook will be damaged and even come off.