Intramolecular excimer formation in diphenylsiloxane-based copolymers

Emission spectra have been measured for well defined poly(dimethylsiloxane-co-diphenylsiloxane)s with different diphenylsiloxane contents and diphenylsiloxane unit distributions in a dilute organic solvent at room temperature and in a rigid glass at 77 K. At room temperature monomer and excimer fluorescence have been observed, the quantum yields of which depend strongly on the diphenylsiloxane content as well as on the diphenylsiloxane unit distribution. At 77 K the emission consists of the monomer fluorescence and phosphorescence, the relative intensity of which is almost independent of the diphenylsiloxane content. Dependence of the monomer and excimer fluorescence yields on the diphenylsiloxane content and diphenylsiloxane unit distribution has been analysed.