Photoimpulsive dispersive relaxation of the effective chi((2)) in binary lead-silicate glasses

We have performed a detailed investigation of the readout decay of optically encoded second-harmonic generation in bulk lead-silicate glasses. The data show that over several decades of readout pulses, the relaxation is a stretched exponential in the pulse number. A new photoimpulsive dispersive transport model, in which the experimental data on the order of the optical process and the depth of the trap distribution below the mobility edge have been included, is used to explain the results.