The authors introduce a new approach to study phase sepn. phenomena in polymer blends. The crystn. of poly(vinylidene fluoride) (I) in a 60:40 blend with Me methacrylate-Me acrylate copolymer (II) is investigated using triple-resonance 1H-13C-19F cross-polarization magic-angle spinning NMR. This technique enables the detn. of the fractions of II and I that are not mixed at a mol. scale. DSC measurements are performed which give information about the degree of crystallinity in the blend. The presence of an amorphous I interphase is found, confirming recent studies on the existence of such an interphase upon crystn. The different crystn. behavior between a 60:40 II-I blend annealed at 120 Deg and a blend annealed at 140 Deg suggests the existence of an upper crit. soln. temp. for this system.