Dynamics of Thermoluminescence under Dual-Wavelength Vis–IR Laser Excitation of Eosin Molecules in a Polyvinyl Butyral Film Containing Oxygen and Silver Nanoparticles

Abstract

Electronic and vibrational energy transfer processes taking place in molecular complexes in a polymer are investigated under dual-wavelength (visible at λ = 532 nm and IR at wavelength λ = 10.6 μm) laser photoexcitation of eosin molecules (С = 4 × 10^–4 М) in air and without it (р ≈ 10^–4 Torr) in thin polyvinyl butyral (PVB) films containing silver nanoparticles (R ≈ 36 nm) prepared by laser ablation. Generation of singlet oxygen, singlet–triplet annihilation, and enhancement of plasmon quenching of dye fluorescence are studied. Thermal-energy transfer processes in thin PVB films following pulsed IR excitation are simulated, and the temperature conductivity coefficients of the polymer films in the presence of silver nanoparticles are calculated. Low-temperature processes in PVB films containing dye molecules taking place after IR excitation are investigated, and the mechanism for accelerating intercombination S₁ → Т₁ transitions as a result of thermal heating and intramolecular vibrational-energy distribution is explained.