photochromic, a. and n.
(fəʊtəʊˈkrəʊmɪk)
[f. as next + -ic.]
A. adj. Of, pertaining to, or displaying photochromism.
| 1953 Jrnl. Chem. Physics XXI. 1619/2 In those compounds which exhibit both thermochromism and photochromism the thermochromic and the photochromic colors are in each case spectroscopically identical. 1965 New Scientist 29 Apr. 291/3 Silver halide particles dispersed through this sheet of ‘photochromic’ glass..cause the glass to darken on exposure to light, and clear again within minutes. 1971 H. Meier in K. Venkataraman Chem. Synthetic Dyes IV. vii. 427 The photochromic reaction of aqueous solutions of the leucosulfite of parafuchsine could be used as a UV dosimeter for the measurement of the UV radiation of sky light. 1974 Observer (Colour Suppl.) 13 Oct. 18/4 Photochromic lenses that automatically change the darkness of their tint to match the prevailing brightness. |
B. n. A photochromic substance.
| 1965 Guardian 13 Apr. 14/5 Sunglasses which are clear in ordinary daylight but which darken progressively in increasing sunlight, were among the practical applications of photochromics described in London yesterday. 1970 Physics Bull. Nov. 487/1 Two other classes of material which have been developed recently as promising photochromics..are the alkaline earth fluorides and titanates. |
Hence ˌphotochroˈmicity = photochromism.
| 1966 Applied Optics V. 946/2 The size of the silver halide microcrystals embedded in the glass matrix determines not only the photochromicity but also the character of the unexposed material (transparent, translucent, and opaque). |