Optical switching,photophysical, and electrochemical behaviors of pendant triazole‐linked indolylfulgimide polymer

Triazole‐linked 2‐indolylfulgimide polymer has been synthesized and its photochromic switching behavior has been characterized by NMR, IR, GPC, TGA, DSC, and UV–Vis spectroscopy. The synthesized photochromic polymer showed absorption peak maxima at 386 and 510 nm wherein the absorption at 510 nm was attributed to charge transfer from triazole ring nitrogen to carbonyl carbon of fulgimide unit. Fluorescence lifetime studies on exciting at 550 nm reveals triexponential behavior with fluorescence decay around 0.1, 1 and 4.2 ns, which correspond to open (E), closed (C) form of fulgimide and triazole ring, respectively. Whereas exciting at 470 nm evidences biexponential fit with fluorescence decay around 0.1 and 2.2 ns, which corresponds to the closed (C) form and triazole ring, respectively. Fluorescence decay of triazole ring was found to be influenced by the excitation wavelength. The cyclic voltammogram of open form of polymer depicts irreversible reductive wave at ?1.4 V. On illumination with 360‐nm light, the reduction wave of polymer was shifted toward less cathodic wave at ?0.9 V; this leads to formation of the closed form of fulgimide unit. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011