Synthesis, chiroptical properties and photoinduced linear birefringence of the homopolymer of (R)-3-methacryloyloxy-1-(4′-cyano-4-azobenzene)pyrrolidine and of the copolymers with the enantiomeric monomer

We have investigated a new optically active photochromic homopolymer poly(R)-3-methacryloyloxy-1-(4′-cyano-4-azobenzene)pyrrolidine] containing in the side-chain a chiral group of one prevailing configuration linked to a trans-azoaromatic system. As expected it exhibits in solution homogeneous conformations with a prevailing chirality induced by dipole-dipole interactions between side-chain chromophores. Copolymers with the enantiomeric monomer (S)-3-methacryloyloxy-1-(4′-cyano-4-azobenzene)pyrrolidine have also been prepared in order to evaluate the effect on the photoinduced optical properties of side-chain chiral groups of opposite configuration in various ratios. The possibility of producing reversible photomodulation of linear birefringence without any significant degradation of these materials seems to be promising for their use in optical data storage.