The evolution of the morphologies in blends of epoxy/4,4'-methylenebis(2,6-dimethylaniline)/polyethersulfone was followed by time-resolved light scattering, optical microscopy and scanning electron microscopy. The results suggest that, once the diffusion of epoxy molecules cannot follow the geometrical growth, a secondary phase separation occurs, even in the droplet morphology, in which the size of the epoxy-rich domain grows as usual. The viscoelastic effect of polyethersulfone is also discussed.