Phosphorescence peculiarities and structure of glassy benzophenone

Abstract

The results of a comparative analysis of spectral-luminescent properties of crystalline and glassy benzophenone are presented. The main spectral characteristics of glassy benzophenone (frequencies of pure electronic transitions in the phosphorescence spectra, band half-widths, relative quantum yields) have been found to possess a number of significant features in comparison with the crystalline phase in the temperature range of 4.2–220 K. Temperature-dependent structural changes in benzophenone have been studied by differential scanning calorimetry. The possibilities of phase transition appearance in benzophenone and their sequences have been shown to be different during cooling and heating the samples. The relationship between the spectral characteristics of various benzophenone phases and their transition temperatures has been demonstrated. To explain the experimental results, the model concepts describing the processes of charge carrier transport and transfer of electronic excitation energy in disordered amorphous and glassy molecular systems, as well as information on the structural features of glasses, have been used.