EXCITED-STATE RELAXATION PROCESSES IN POLYMETHINE DYE MOLECULES IN POLYMERIC MEDIA

The fluorescence decay kinetics of polymethine dye molecules in liquid (ethanol) and solid (polyurethane acrylate) media has been measured. Absorption-relaxation-emission processes are studied at wide range of excitation wavelengths (from blue to red edge of absorption band), emi ssion wavelengths (including anti-Stokes fluorescence) and of temperat ure (both in elastic and glassy states of polymeric medium). Time-reso lved fluorescence spectra of dye molecules in polymer confirm that, in spite of macrorigidity of polymeric medium, the characteristic time o f relaxation processes within the excited state is comparable to the f luorescence lifetime.