Synthesis of novel polyurethanes containing dioxybenzylidenecyanoacetate, as non‐linear optical chromophores and their properties

Abstract

Methyl 3,4-di-(2′-hydroxyethoxy)benzylidenecyanoacetate (3) was prepared by hydrolysis of methyl 3,4-di-(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, 5 and 6 containing the non-linear optical (NLO) chromophore 3,4-dioxybenzylidenecyanoacetate. The resulting polyurethanes 4–6 were soluble in common organic solvents such as acetone and DMF. Tg values of the polymers obtained from DSC thermograms were in the range 80–102 °C. Polymers 4–6 showed thermal stability up to 300 °C in TGA thermograms, and electro-optic coefficients (r33) of the poled polymer films were in the range 10–12 pm V−1 at 633 nm, which are acceptable for NLO device applications. © 2002 Society of Chemical Industry