Luminescence property of poly(1,3-bis(phenyl-1,3,4-oxadiazole))s containing polar groups in the main chain

Photoluminescence properties of a new series of soluble 1,3-bis(phenyl-1,3,4-oxadiazole)s bearing polar groups in the main chain like -NO2, −OH, −CH3 and -Cl have been studied. The photoluminescence spectra show significant shift in the emission wavelengths in solid as well as in solution depending on the groups attached in the main chain, both redshift (electron withdrawing group) and blueshift (electron donating group) and change in the intensity of the emissive spectra as compared with those of the simple polyoxadiazoles at ∼300 nm. Quantum yield measurement with reference to anthracene indicates increase in the quantum efficiency many folds with decrease in concentration. The polymers are found to be thermally stable up to 350-400 °C and their glass transition temperature ranges between 100 and 150 °C.