EARLY-STAGE OF SPINODAL DECOMPOSITION IN 2D

A qualitative description of a spinodal decomposition kinetics is prop osed. It is made of a linear stage followed by two nonlinear stages, l eading, respectively, to higher and lower frequency generation in the spatial order parameter distribution, then followed by the classical O stwald ripening. This general scheme is supported by a specific experi mental study. It concerns the two-dimensional thickness demixion of co polymer thin films made of three to four bilayers.