Scotophor

A scotophor is a material showing reversible darkening and bleaching when subjected to certain types of radiation. The name means dark bearer, in contrast to phosphor, which means light bearer. Scotophors show tenebrescence (reversible photochromism) and darken when subjected to an intense radiation such as sunlight. Minerals showing such behavior...
Found on http://en.wikipedia.org/wiki/Scotophor

scotophor

scotophor Material, usually potassium chloride, that darkens under electron bombardment and is used for screens of cathode-ray tubes.
Found on http://www.wordinfo.info/words/index/info/view_unit/1917/2
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