Synthesis of novel Y-type polyurethane containing azomethine moiety, as non-linear optical chromophore and their properties

3,4-Di-(2′-hydroxyethoxy)-4′-nitrobenzylidene II was prepared by condensation reaction of 3,4-dihydroxy-4′-nitrobenzylidene I with 1-chloro-2-ethanol. Monomer II was reacted with p-phenylene diisocyanate to yield polyurethane containing the non-linear optical chromophore 3,4-di-(2′-hydroxyethoxy)-4′-nitrobenzylidene. Polymer III shows thermal stability up to 300 °C in TGA thermogram. Tg value of the polymer obtained from DSC thermogram was 110 °C. The resulting polyurethane III was soluble in common organic solvents such as acetone, DMF and DMSO. The values of electro optic coefficient d33 and d31 of the poled polymer film were 3.15 × 10 −7 and 1.5 × 10 −7 esu, respectively.