Patent ID: 6436525
Filing Date: 2002-08-20
Classification: C09K,G02B,G03C,Y10T

Abstract:
An article comprising, in combination, a substrate and a photochromic polyanhydride coating on at least one surface of said substrate, said photochromic polyanhydride coating being prepared from components comprising: (a) the reaction product of hydroxyl-functional component(s), and polymeric anhydride-functional component(s) and (b) a photochromic amount of photochromic compound(s), said components being used in such proportions to produce a photochromic coating having a Fisher microhardness of at least 50 and not more than 130 Newtons per mm2, and photochromic properties characterized by a &Dgr;OD of at least 0.15 after 30 seconds and at least 0.50 after 15 minutes, and a bleach rate of not more than 200 seconds âˆ’all as measured at 72Â° F.