Dispersive kinetics of nonphotochemical hole burning and spontaneous hole filling: cresyl violet in polyvinyl films

The dispersive kinetics of nonphotochemical burning and spontaneous filling of the zero-phonon hole of Cresyl Violet in polyvinyl alcohol at 1.6 K are analyzed in terms of the standard external two-level system (TLS{sub {ital ezt}}) model for probe--glass systems and a distribution function for the tunnel frequency derived from a normal distribution function for the tunnel parameter {lambda}. Average values for the relaxation rates for burning and filling are determined. It is shown that the dominant mechanism for filling is not global spectral diffusion but rather antihole reversion. A high degree of positive correlation between the rates of burning and filling associated with the TLS{sub {ital ext}} is found. A new methodology that permits a more physically reasonable interpretation of spontaneous hole-filling kinetics is described. It is based on the hypothesis that only a fraction of burned sites, on reversion to the ground state, yield sites with resonance frequencies that lie within the hole profile.