Effects of Fluorescence and Energy Transfer in Polystyrene under Excitation in the Vacuum Ultraviolet

Abstract

The emission spectrum of solid polystyrene is investigated as a function of excitation wavelength in the region 2540–1216 Å, for various modes of preparation (solid machined disks, films, evaporation layers) and treatment (heating, polishing, etc.). A strong dependence of the spectral distribution on excitation wavelength is observed. Exciting radiation which is more strongly absorbed produces a fluorescence spectrum extending to longer wavelengths. A strong influence of the mode of preparation and treatment of the sample on the fluorescence spectrum is observed. The results are tentatively interpreted as representing the strong influence of the solid‐state structure of the material on intermolecular interactions between segmers. The fluorescent quantum yield of solid solutions of diphenyloxazole and of anthracene in polystyrene is investigated as a function of the excitation wavelength in the region 3164–584 Å. A strong variation of the quantum yield with excitation wavelength is observed. The results are interpreted in terms of a competition between solvent—solvent and solvent—solute interactions, the probability of each depending on excitation wavelength. The difference in behavior of solutions of PPO and solutions of anthracene is discussed.