From: utzoo!decvax!harpo!seismo!rocheste!bill
Newsgroups: net.followup
Title: Re: A strange idea for a new type of memory
Article-I.D.: rocheste.142
Posted: Mon Nov  1 14:47:41 1982
Received: Tue Nov  2 04:00:05 1982
References: watmath.3751

Photochromic materials were indeed tested for use as a memory medium
and NCR was one of the principal researchers (in the 1960's).  The 
essential drawbacks of these materials for use as computer memories are:
insensitivity, fatigue, and fading.  A good deal of light (energy) is required
to induce a color change, hence insensitivity.  The material will fatigue after
many writes (the image fades over time).  EG&G put a photochromic dye
(triarylmethane ?) behind two quartz windows in goggles and used a Xenon flash-
lamp to trigger the photochromic reaction.  The flashlamp was triggered by the
light from a nuclear detonation.  These goggles are designed to protect the 
vision of fly-boys.

Bill Lampeter
R.I.T. Photographic Science