Liquid crystal polymers containing permanent dipole azobenzene chromophores

Three photochromic monomers containing a permanent dipole photochromic azob enzene group spaced from the methacryloyl moiety by a polymethylene segment were synthesized in three steps starting from 4-cyanoaniline. The monomers were homopolymerized and copolymerized with an optically active monomer, ( -)-menthyl methacrylate, in the presence of AIBN as a radical initiator. St ructurally similar amphiphilic polymers were obtained by homopolymerization of analogous methacrylates in which oligo(oxyethylene) segments replaced t he polymethylene spacers. The polymeric materials, having a molar content o f photochromic units between 5 and 100% and molecular weights of about 15,0 00, were characterized by thermal analysis, X-ray diffraction, 1D and 2D NM R. Mobility and photochromic properties in solution were also investigated.