Photochromism

A photochromic eyeglass lens, after exposure to sunlight while part of the lens remained covered by paper.

Photochromism is the reversible change of color upon exposure to light. It is a transformation of a chemical species (photoswitch) between two forms by the absorption of electromagnetic radiation (photoisomerization), where the two forms have different absorption spectra.^[1]^[2]

^ Irie, M. (2000). "Photochromism: Memories and Switches – Introduction". Chemical Reviews. 100 (5): 1683–1684. doi:10.1021/cr980068l. PMID 11777415.
^ Heinz Durr and Henri Bouas-Laurent Photochromism: Molecules and Systems, ISBN 978-0-444-51322-9

[Irie2000-1] Irie, M. (2000). "Photochromism: Memories and Switches – Introduction". Chemical Reviews. 100 (5): 1683–1684. doi:10.1021/cr980068l. PMID 11777415.

[2] Heinz Durr and Henri Bouas-Laurent Photochromism: Molecules and Systems, ISBN 978-0-444-51322-9

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