Reminiscences About Organic Photochromics

Abstract
The history of organic photochromies for potential military and commercial applications, especially the efforts at NCR Corp. during 1955–1972, is recalled. Impractical then because of “fatigue,” organic photochromies are now useful for ophthalmic lenses, optical information processing, and photocontrol of physical properties and biological activity of polymers, because of the development of fatigue-resistant dyestuffs and a better understanding of the interactions between the dyestuff and its matrix.