Absolute viscosities of dilute solutions of poly(vinyl chloride) (PVC) in cyclohexanone and in its blends with xylene were determined at temperatures ranging from 5 to 50 degrees C and in THF at 5-30 degrees C. The simple Arrhenius reaction kinetics equation, used by Anrade to analyze the viscosity data of liquids and later by Moore for dilute polymer solutions, was used to estimate the thermodynamic parameters for the flow of PVC solutions and the quality of solvents. This relationship was also used to calculate thermodynamic parameters for PVC in binary solvent systems. The data of the activation energy of the viscous flow and preexponential factor were further analyzed by using the empirical relationships suggested by Moore for flexible polymer chains. The parameters obtained from these relationships are used to estimate and compare the solvency power of solvents and solvent blends. A blend of 1 : 1 cyclohexanone and xylene is found to have better dissolution characteristics for PVC than have cyclohexanone and other blends.