PHOTORESPONSIVE POLYMERS - REVERSIBLE SOLUTION VISCOSITY CHANGE OF POLY(METHYL METHACRYLATE) HAVING SPIROBENZOPYRAN SIDE GROUPS

Poly(methyl methacrylate) having spirobenzopyran side groups was synthesized in an attempt to construct a photoresponsive polymer, the conformation of which can be photoregulated. Solution viscosity of the polymer was reduced during irradiation and returned to the initial value after removing the light in benzene. The decrease/recovery cycles of the viscosity can be repeated many times without any noticeable fatigue. Solvent effects, as well as spectroscopic studies including laser photolysis, indicate that the photodecrease in viscosity is caused by intramolecular solvation by the methacrylate ester side groups of the polar merocyanines which are produced by irradiation of the spirobenzopyran side groups. © 1979, American Chemical Society. All rights reserved.