This book is focused on testing of free volume theory against experimental data. Residual solvent content, the concentration of solvents, and polymer have been plotted with time. Four binary polymer-solvent systems have been studied. Poly(styrene)-tetrahydrofuran, poly (styrene) - p-xylene, poly(methyl methacrylate) - ethylbenzene, and poly(methyl methacrylate) - tetrahydrofuran, systems have been studied. Governing transport equation is a non-linear partial differential equation that has been solved using Galerkin's finite element weighted residual method which converts it into the systems of the ordinary differential equations. Ordinary differential equations have been solved using three point Gauss quadrature method using MATLAB package. Self-diffusion coefficients were estimated using free volume theory; few parameters which were not the pure component properties needed for the theory were estimated by minimizing the difference between weight loss predicted by the drying model and that measured experimentally.