noun
photochromic glass
Glass that darkens when exposed to light and clears when light is removed, commonly used in eyeglasses and windows.
このメガネはフォトクロミックガラスを使っているので、外に出るとすぐに色が変わる。
These glasses use photochromic glass, so the tint changes as soon as you go outside.
Variant with interpunct, sometimes used for clarity.
Loanword from English 'photochromic glass'.