photochromic

American  

[foh-tuh-kroh-mik] / ˌfoʊ təˈkroʊ mɪk /

adjective

1. (of chemically treated glass or plastic) capable of darkening or changing color when exposed to light.

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photochromic British  

/ ˌfəʊtəʊˈkrəʊmɪk /

adjective

1. (of glass) changing colour with the intensity of incident light, used, for example, in sunglasses that darken as the sunlight becomes brighter

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Other Word Forms

• photochromism
  noun

Etymology

Origin of photochromic

First recorded in 1950–55; photo- + chrom- + -ic

Example Sentences

"Think of photochromic sunglasses. When you're inside, they're just clear lenses. You walk out into the sun, and they darken on their own. Come back inside, and the lenses become clear again," Nguyen continued.

From Science Daily • May 15, 2026

The physical design is all new, combining thin flat sides with a curved back panel that, at least on the “sunrise blue” model, uses a photochromic layer that changes color under exposure to sunlight.

From The Verge • Feb. 16, 2022

I also wanted photochromic lenses that would darken in sunlight.

From Los Angeles Times • Jan. 11, 2022

Prescription readers also can be made with photochromic lenses that darken in bright light.

From Washington Post • Mar. 23, 2020

A recent development is photochromic lenses, which darken in the sunlight and become clear indoors.

From Textbooks • Aug. 12, 2015