Recent experimental results indicate that the inscription of gratings in DR1:DNA-CTMA thin films displays some features of non-exponential grating amplitude growth with time.1 The origin of this behavior is hypothetically assigned to a complex distribution of local voids in a polymeric matrix1, 2 which strongly influences the dynamics of grating inscription modelled using the semi-intercalation hypothesis.3–7 We discuss critically those topics, review the theoretical methods used for modelling of the grating inscription and point-out a hypothetical relation to complex systems. New experimental results of holographic DTWM recording of the gratings in DNA-CTMA:DR1 and PS:DR1 are presented. The two observed types of dynamics are hypothetically assigned to various distributions of local voids in corresponding polymeric matrices.