The morphological changes of PVC plastisols during gelatin and fusion were characterized by adopting sma1l-angle light scattering(SALS) method. SALS provided in situ observation of swelling behavior of PVC particles as well as quantitative information of average size of the particles while they are in the process of swelling with plasticizer during gelatin and fusion. In addition, SALS enabled one to evaluate the solvent power of plasticizers, which agrees well with the rheological results discussed in Part I of this series.