Temperature and Pressure Dependence of Phosphorescence Lifetimes in PMMA

Abstract

The phosphosescence lifetimes of 1,2,5,6‐dibenzanthracene and triphenylene have been measured in polymethylmethacrylate as a function of temperature (77–360°K) at 1 atm and 30 kbar. Two temperature regimes with different activation energies are discernible for both compounds. Matrix compression has negligible influence on the ∼200‐cm−1activation energy below room temperature, but diminishes the larger activation energy (1500–4500 cm−1) above room temperature by 20%–25% at 30 kbar. The pressure data suggest that diffusional quenching is not responsible for the thermally activated process(es).