Environment effects on the optical properties of some fluorinated poly(oxadiazole ether)s in binary solvent mixtures

The solvatochromic behavior of some fluorinated poly(oxadiazole ether)s was studied using UV-vis absorption and fluorescence spectroscopy in neat solvents and in their solvent mixtures at several ratios of cosolvents. Quantitative investigations of the spectral changes caused by solvent polarity were discussed using the Lippert‐Mataga, Bakhshiev and Kawski-Chamma-Viallet polarity functions. Repartitioning of cosolvent between local (solvation shell) and bulk phase was investigated by means of a solvatochromic shift method in chloroform-N,N-dimethylformamide (CHCl3/DMF) and chloroform-dimethyl sulfoxide (CHCl3/DMSO) solvent mixtures. Solvatochromic properties in the binary solvent environments were predominantly influenced by the acidity and basicity of the solvent systems. The fluorescence quenching process by nitrobenzene was characterized by Stern-Volmer plots which display a positive deviation from linearity. This was explained by static and dynamic quenching mechanisms.