Synthesis and switching properties of photochromic carbazole–spironaphthoxazine copolymer

A photochromic switching copolymer was synthesized by typical radical copolymerization of 2-(9H-carbazol-9-yl) ethyl methacrylate, a vinyl monomer having a spironaphthoxazine residue. It reversibly changed the fluorescent intensity by alternative irradiation with ultraviolet and visible light probably due to the photoinduced electron transfer (PET) between carbazoles and the open form of spirooxazine (SPO) moiety. By the observation of photoresponsive viscosity and conductivity changes, it was confirmed that the copolymer could exhibit excellent viscosity and conductivity switching behaviors.