Fourier transform infrared (FTIR) spectroscopy, optical microscopy (OM), and differential scanning calorimetry (DSC) techniques were used to probe phase behavior and interactions in blends of poly(vinylidene fluoride) (PVDF) and polyesters [poly(trimethylene adipate) (PTA) and poly(pentamethylene adipate) (PPA)] of relatively low crystallizability. DSC thermal analysis and OM characterization proved that PVDF was miscible with PTA and PPA with a low lower critical solution temperature. Small negative values of the interaction parameters (chi(12) = -0.13 for a PVDF/PPA blend) were obtained with the meltingpoint depression method. FTIR spectroscopy results revealed that interactions between -CF2 of PVDF and the -C=O group of the polyester were weak, in agreement with the thermal analysis results. An increase in the coarseness and/or ring-band spacing further provided supportive evidence that miscibility did exist between the polyester and PVDF constituents in the blends. Pattern changes in ring-band spherulites of the miscible blends further substantiated the favorable, though weak, interactions between the PVDF and polyester constituents. (C) 2007 Wiley Periodicals, lnc.