What is photochromic glass?

Photochromic glass is optical type of glassthat darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet radiation. In the absence of activating light, the glass return to their clear state. Photochromic be made of glass, polycarbonate, or another plastic. If you are planning to install it at your house be wise on hiring a glass service for your glass upgrade at home.

Photochromic lenses are eyeglass lenses that are clear (or nearly clear) indoors and darken automatically when exposed to sunlight.

Other terms used for photochromic lenses include "light-adaptive lenses" and "variable tint lenses."