Optical energy transfer and trapping in 9-aminoacridine doped sol-gel glasses

Time-resolved fluorescence lifetime and depolarization results are presented for 9-aminoacridine (9AA) doped silicate (SX) and aluminosilicate xerogel (ASX) glasses. At low concentrations the dynamics are dominated by donor-donor energy transfer processes, however, energy trapping by aggregate species is observed at higher concentrations. In addition, a comparison of the anisotropy decay rates and the critical radius obtained from the spectral overlap indicates a significant excluded volume within the xerogel matrix. An unresolved fast anisotropy decay component for 9AA doped ASX may suggest a non-random spatial distribution of chromophores within the occupied restricted volume of the ASX matrix.