OPTICAL-ENERGY TRANSFER AND TRAPPING IN 9-AMINOACRIDINE DOPED SOL-GELGLASSES

Time-resolved fluorescence lifetime and depolarization results are pre sented for 9-aminoacridine (9AA) doped silicate (SX) and aluminosilica te xerogel (ASX) glasses. At low concentrations the dynamics are domin ated by donor-donor energy transfer processes, however, energy trappin g by aggregate species is observed at higher concentrations. In additi on, a comparison of the anisotropy decay rates and the critical radius obtained from the spectral overlap indicates a significant excluded v olume within the xerogel matrix. An unresolved fast anisotropy decay c omponent for 9AA doped ASX may suggest a non-random spatial distributi on of chromophores within the occupied restricted volume of the ASX ma trix.