Three novel experimental techniques have been developed to study the phase separation dynamics and morphology of polymer-polymer blends. Samples prepared from different materials by different methods appear to follow the same phase transformation behavior. The minor phase, dispersed as discrete particles, may change its phase morphology by aggregation and coalescence. The aggregation process involves the change in either particle location (small particles may translate) or particle geometry (to reduce interfacial area). Once the interparticle contact is effected, the flattened interface will break and allow for sintering of particles. The particle size distribution is more or less random and tends to broaden with time. The volume fraction of the second phase has a substantial effect on its growth rate. It has been demonstrated that a combination of hot-staged optical microscopy, transmission electron microscopy, high-speed cinematography, and the three novel sample preparation techniques facilitate a detailed study on the late-stage mechanisms of phase separation of polymeric blends.