SPECTRAL DIFFUSION IN AN AMORPHOUS POLYMER PROBED BY SINGLE-MOLECULE SPECTROSCOPY

We investigated the spectra of single tetra-tert-butylterrylene (TBT) molecules in the amorphous matrix poly(isobutylene) (PIB). The distrib ution of line widths of TET in PIB was measured and compared to that o f TBT in poly(ethylene). The fluorescence intensity autocorrelation fu nction as well as the two-point frequency autocorrelation function wer e determined for different single TBT molecules. Logarithmic-like deca ys of the fluorescence autocorrelation function could be reproduced by assuming a 1/R fluctuation rate distribution for the two-level-tunnel ling systems.