Temperature Dependence of Phosphorescence Characteristics of Aromatic Hydrocarbons in Poly(methylmethacrylate)

Abstract

The thermal dependence of the phosphorescence parameters of a number of aromatic hydrocarbons has been studied in poly(methylmethacrylate) in the range 77–400°K. The data generated here, as well as that available elsewhere in the literature, has been analyzed in terms of two distinct temperature‐dependent triplet‐depletive processes: The process dominant in the low‐temperature regime is probably intramolecular; the process which predominates at higher temperatures is intermolecular and represents a thermally assisted energy transfer from the lowest triplet state of the guest solute,T 1G , to a state of the host plastic at 25100±500 cm−1. The ``plastic'' state is thought to be a triplet and is denoted T 1P . Some independent evidence for the T 1P designation is also provided.