Hologram decay results are presented concerning a time varying decay rate which can be explained on the basis of a time dependent conductivity given by &sgr;=&sgr;0+&sgr;1 exp(−t/&tgr;T). An analysis based on this assumption describes the data well, giving strong support for the existence of a persistent photoconductivity component during decay. The effective time constant &tgr;eff? ln&eegr;/∂t)−1is dicsussed in terms of this component and the dark conductivity.