New aromatic polyethers containing phenylquinoxaline and 1,3,4-oxadiazole rings

A series of new heterocyclic polyethers, containing phenylquinoxaline and 1,3,4-oxadiazole rings, was synthesized by polycondensation of bis (4-fluorophenyl)-1,3,4-oxadiazole with a diphenol containing preformed phenylquinoxaline rings. These polymers showed good solubility in chloroform and gave transparent, flexible films, by casting their solutions onto glass plates. They exhibited glass transition temperatures in the range of 225–337°C and were stable when heated up to 420°C, the initial decomposition temperature being in the range of 425–465°C. Solutions of these polymers in chloroform exhibit violet fluorescence, having maximum emission wavelength in the range of 412–425 nm and fluorescence quantum yield in the range of 0.11–0.26. The polymer films displayed a low dielectric constant and tough mechanical properties.