In creating thin films of polymers by solution processing, a common problem is the undesirable formation of bubbles during the drying process. Practical experience shows that bubbles can be created well below the boiling point of the solvent. Also, it has been observed that the degassing of the polymer solutions results in reduced bubble formation, and this indicates a relationship between the presence of air and bubble formation. This work is based on the hypothesis that if the solubility of air in the polymer solution increases with the solvent concentration, then the solution can become supersaturated with air as the concentration of the solvent is reduced during the drying process. To test this hypothesis, knowledge of the thermodynamics of the mixture is required. This study concentrated on the system of poly(vinyl acetate), toluene, and nitrogen. A thermodynamic model to predict phase behavior of this system was developed. The solubility of nitrogen in poly(vinyl acetate) and poly(vinyl acetate)-toluene as a function of the toluene composition over wide ranges of temperatures and pressures was measured with the pressure decay technique. The group-contribution lattice-fluid equation of state was employed to correlate the thermodynamic behavior of the binary and ternary systems. In addition, experiments were conducted to measure the diffusion coefficients of the nitrogen in poly(vinyl acetate). (c) 2008 Wiley Periodicals, Inc.