A novel polyurethane containing main-chain electron donating-accepting azobenzene chromophores has been prepared. Compound (Ⅰ) 4-carboxyl-4′[(2-hydroxyethyl)-ethylamino]-azobenzene was synthesized from azo coupling reaction between p-aminobenzoic acid and N-ethyl-N-hydroxyethylaniline．Monomer (Ⅱ) 4-[(2-hydroxyethyl)ethylamino]-4′-(2-hydroxyethyloxycarbonyl) azobenzene was obtained by reaction between (Ⅰ) and 2-chloroethanol．The chemical structure and purity of the compound (Ⅰ) and monomer (Ⅱ) were confirmed by the characterization of 1H-NMR

FTIR and UV-Vis spectrometry．Through the polymerization reaction between azo monomer(Ⅱ) and TDI

the azo polymer was obtained．The chemical structure of polymer was characterized by 1H-NMR、FTIR and UV-Vis spectrometry．The molecular weight and its distribution were determined by GPC to be Mn=4800 with a polydispersion index 1.3．From DSC thermogram

a glass transition temperature of 119℃ was observed．The polymer synthesized exhibits significant photodynamic behavior. Surface profile gratings were optically inscribed upon exposure to an interference pattern of Ar+ laser beam at modest intensities．The surface modulation was about 220 nm and the first order of diffraction efficiency was up to 24％.