*Photo taken from Rudy Project North America
Photochromic glass is one example of composite material. Composite material is a structural material that is formed by combining two or more different substances. The resulting material has properties that are superior than those of the original components.
A photochromic glass is produced by embelding a layer of silver halides(usually silver chloride) in glass or transparent plastic.
Photochromic glass darkens when is exposed to sunlight. When the light dims, it become transparent again. It is suitable for making optical lenses, windshields and windows.