A new diol with bistriazene groups, 1,1'[4,4'diphenylether]-3,3'-di(beta-hydroxyethyl methyl)-bistriazene (BTD), was synthesized and characterized. BTD, along with N-methyldiethanolamine as a chain extender, was used to prepare a segmented polyurethane based on poly(tetramethylene oxide) diol (weight-average molecular weight = 2000) and 2,4-totylene diisocyanate (80:20 v/v 2,4-/2,6-isomer mixture). Subsequent quaternization of the amine with benzyl chloride formed the cationomer. The structure-property relationships, including the photochemical behavior of the triazene linkage in these polymers, were investigated with respect to another polyurethane prepared from 4,4'-diphenylmethane diisocyanate and a bistriazene compound. Photolysis experiments were carried out in polymer solutions and in the film state, and the reduction of the pi-pi* absorption band, characteristic of the triazene chromophore in ultraviolet spectra, was followed. A kinetic evaluation revealed a first-order photoprocess. (C) 2005 Wiley Periodicals, Inc.