Synthesis, structure, and properties of bifunctional azobenzene monomers and polymers on their basis

A new preparative procedure for the synthesis of new bifunctional azo monomers with different ratios of methacryloyl and hydroxyl groups has been developed. The monomers thus prepared contain a nonlinear optical 4′-amino-4-nitroazobenzene group and can be involved in polymerization, polycondensation, and polymer-analogous transformation reactions to afford linear and network polymers. The free-radical copolymerization of 4′-[N-methyl-N-(3-methacryloyloxy-2-hydroxypropyl)]amino-4-nitroazobenzene with methyl methacrylate has been studied with the aim of preparing azobenzene [1+0] prepolymers with pendant chromophore groups, and the reactivity ratios and reactivity factors of the comonomers have been calculated. The hydroxyl-containing copolymers are characterized by rather high molecular mass, satisfactory heat resistance and thermal stability, and good film-forming behavior. These copolymers may be crosslinked with the use of diisocyanates and thus may form thin optically homogeneous red films.