Synthesis of polyurethanes containing dioxynitrostilbene as a NLO-chromophore and their properties

Summary 3,4-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (2) were prepared by the reaction of 2-iodoethanol with 3,4-dihydroxy-4'-nitrostilbene (1). Diol 2 was condensed with 2,4-toluenediisocyanate and 3,3'-dimethoxy-4,4'-biphenylenediisocynate to yield polyurethanes 3 and 4 containing the NLO-chromophore 3,4-dioxy-4'-nitrostilbene. Polymers 3 and 4 were soluble in common organic solvents such as acetone and DMSO. T _g value of the resulting polymers was in the range of 109–114°C. Electrooptic coefficient (r₃₃) of the poled polymer films were in the range of 20–25 pm/V at 633 nm. Polymers 3 and 4 showed a thermal stability up to 300°C in TGA thermograms, which is acceptable for NLO device applications. Received: 29 September 1999/Revised version: 19 November 1999/Accepted: 25 November 1999