Its a chemical reaction. Someone had to stumble onto it by accident. Im sure they are stilll tweaking it and will get it better before too long. Its done just like photography and if your old enough to remember...photos use to turn yellow too, but not anymore.
There are a few guys on pro-touring.com using it, but the problem is it has turned yellow and deteriorated very quickly as soon as it has minimal exposure to sunlight. Its basically the silver you see on the back of a piece of glass that turns it into a mirror. They have tried uv clears etc with no success. As soon as they figure it out it will be great. Its readily available in the US too.