Synthesis and properties of novel polyurethanes containing 2,4-dioxybenzylidenecyanoacetate group as a NLO-chromophore for electro-optic applications

Methyl 2,4-bis-(2'-hydroxyethoxy)benzylidenecyanoacetate (3) was prepared by hydrolysis of methyl 2,4-bis-(2'-vinyloxyethoxy)benzylidenecyanoacetate (2). Diol 3 was condensed with 2,4-toluenediisocyanate, 3,3'-dimethoxy-4,4'-biphenylenediisocyanate, and 1,6-hexamethylenediisocyanate to yield polyurethanes 4-6 containing the NLO-chromophore 2,4-dioxybenzylidenecyanoacetate, The resulting polyurethanes 4-6 were soluble in common organic solvents such as acetone and DMF. Polymers 4-6 showed a thermal stability up to 280degreesC in TGA thermograms with T-g values obtained from DSC thermograms in the range of 66-114degreesC. The SHG coefficients (d(33)) of poled polymer films were around 7.8 x 10(-9) esu.