Phosphorescence Peculiarities and Structure of Glassy Benzophenone

Results of a comparative analysis of spectral-luminescent properties of crystalline and glassy benzophenone are presented. The main spectral characteristics (frequencies of purely electronic transitions in phosphorescence spectra, band half-widths, relative quantum yields) of glassy benzophenone have been found to possess a number of significant features as compared to the crystalline phase in the temperature range 4.2–220 K. Temperature-dependent structural changes in benzophenone have been studied by differential scanning calorimetry. The ability of phase transitions to appear in benzophenone and their sequences were shown to differ during cooling and heating of the samples. The relationship between the spectral characteristics of various benzophenone phases and their transition temperatures has been demonstrated. Model concepts describing the transport of charge carriers and the transfer of electronic excitation energy in disordered amorphous and glassy molecular systems and information on the glass structural features have been used to explain the experimental results.