ANOMALOUS SPECTRAL DIFFUSION IN POLYMER GLASSES

Spectral diffusion (SD) in PMMA samples, doped with Zn-tetrabenzoporph yne, was investigated via populational hole burning in the absorption spectrum of a chromophore on a time scale 20 mu s-150 ms and in a temp erature interval of 1.7-10 K. An anomalous increase of the SD rate was found in the millisecond range, which cannot be attributed to peculia rities in the relaxation rate distribution of the two-level systems in PMMA. The apparent correlation of the anomalous SD region with the ti me domain of chromophore triplet state deactivation cannot be explaine d in the framework of existing SD models.