EFFECTS OF THE SOLID-LIQUID INTERFACE ON THE EXCIMER FORMATION OF PYRENE IN TOLUENE CONTAINING POLY(METHYL METHACRYLATE) - A TIME-RESOLVED TOTAL INTERNAL-REFLECTION FLUORESCENCE STUDY

By means of time-resolved total internal reflection (TIR) fluorescence measurements, rise and decay profiles of the pyrene excimer fluorescence were examined in toluene containing 3.3 x 10(-4) mol dm-3 of poly (methyl methacrylate) (PMMA, MW = 1 20000). In addition to a reduction of the fluorescence intensity of the pyrene excimer relative to the monomer, the rise and decay rates of the excimer fluorescence were decelerated in a sapphire/toluene interface layer of a thickness less than 60 nm. These findings were interpreted by an increase in the viscosity of the interface layer including PMMA adsorbed on a sapphire surface.