Spectroscopic ellipsometry data are presented that describe the dynamics of the partitioning of a model chromophore (Ru(bPY)(3)(2+)) into a thin porous solid film (Nafion). Backside optical interrogation permitted the study of the film at wavelengths where the bathing solution containing the chromophore significantly absorbed light. Data acquired in situ while the model chromophore Ru(bpy)(3)(2+) partitioned into the film were successfully interpreted using an optical multilayer layer model. This model was constructed by sequential experimental examination of the individual component layers of the system. A quantitative description of the dynamic film was achieved by assembling a model film layer that contained Tauc-Lorentz oscillators to describe both the real and imaginary parts of the refractive index using the Kramer-Kronig relationship. Subsequent analysis of experimental data using the model resulted in a quantitative description of how the optical constants and thickness of the film changed as chromophore Ru(bpY)(3)(2+) partitioned into it from solution. The film's thickness also changed during the course of the partitioning. On the first incorporation of the chromophore, the film contracted and then, as the film approached equilibrium with the bathing solution, re-expanded. Digital simulations of three different chromophore partitioning modes were presented. Analysis of Delta vs Psi plots for the three simulated modes strongly supports a simple uniform optical layer model description of the partitioning process for the Ru(bpY)(3)(2+)-Nafion film system under the prevailing experimental conditions. Overall, the results gave new insights into the acquisition of the data for and associated interpretation of the chromophore-film partitioning process.