An Ultraviolet detector based on the propriety of a photochromic composition in changing its color upon exposure to UV rays is described. The said photochromic composition contains a spiropyran or a spiroxazine molecule previously dissolved in a non-polar solvent such as toluene, cyclohexane, then mixed...http://www.google.es/patents/US5581090?utm_source=gb-gplus-sharePatente US5581090 - Photochromic ultraviolet detector
