Hyperbranched Oligoglycerols and Photochromic Compositions on Their Basis

New photochromic compositions are obtained on the basis of hyperbranched oligoglycerol covalently bound to a methyl methacrylate–maleic anhydride copolymer. The irradiation of such compositions with UV light leads to reversible photoinduced transformations between the cyclic spiropyran and open merocyanic forms of photochromic spiropyran. The kinetics of dark relaxation of the photoinduced merocyanine form to the initial state of the compound incorporated into the given polymer matrix is studied. It is shown that branched compounds with a relatively low molecular weight are efficient for preparing photochromic polymers with a high rate of dark relaxation. It is found that the time of dark relaxation of the polymer composition with a high molecular weight oligoglycerol introduced into the polymer matrix increases sharply.