The dynamics of light-induced gratings in weakly absorbing glasses possessing liquid crystalline orientational order have been investigated using a gated cw-laser. It is shown that structural relaxation processes are substantially important for the formation of reversible holographic storage effects. The resulting complex dynamics of grating formation have been analyzed by applying a time-domain master-plot construction for the first time. Intensity and temperature dependence of the obtained relaxation time exhibits a Vogel-Fulcher behavior and the relaxation process can be described by a stretched exponential law of the Kohlrausch-Williams-Watt type.