Current literature indicates that considerable effort is being made to relate rheological behavior of various materials to molecular mechanisms of flow. Implicit in viscoelastic spectra are the molecular motions and configurations that give shape to the stress relaxation or creep compliance curves. In dilute solutions or concentrated melts at higher temperatures, flow curves give indications of molecular arrangements present which cause deviation from some previously defined standard. Both qualitative and quantitative descriptions of solution and flow mechanisms recognize the importance of intermolecular forces. While these treatments can be used with confidence in systems of low polarity, highly polar solvent‐solute mixtures are not adequately described by these relations. Our primary considerations here are directed at understanding the nature of the interaction of 2‐ethylhexyl carboxylates with poly(vinyl chloride) and its model 1,3‐dichloropropane. The method employed represents a departure from conventional thought in that rheological behavior, from tensile creep compliance, dilute solution, and melt viscosity, has been successfully correlated to both Hammett and Taft substituent constants as implied in Eyring's concept of absolute reaction rates. While changes in interaction free energies between solvent and ester evolve simply and naturally from this technique, the significant conclusion obtained from these data is that the generally accepted “hydrogen‐bonding” interaction hypothesis of poly(vinyl chloride) with esters is clearly absent.