Photoresponsive Polyurethane-Acrylate Block Copolymers.I.Photochromic Effects in Copolymers Containing 6'-Nitro Spiropyranes and 6'-Nitro-bis-Spiropyranes

摘要

The photochromic effect of polyurethane-acrylate block copolymers con-taining 6'-nitro spiropyranes and 6'nitro-bis-spiropyranes has been investigated.The influence of incorporation of the photochromic agent into the polymeric matrix as a simple solid solution or in a chemically bonded form and the effects of the composition (polyurethane-acrylate) of the block copolymer were studied.In general,it was ob-served that the photoresponse for the spiropyranes and especially the bis-spiropyranes obey the combination of several factors,mainly the spatial and electronic differences between the two forms (Sp.-Mer.) in the photoisomerization of these compounds.Such factors are discussed here.