The dissolution of poly(alpha -methylstyrene) (PAMS) by a binary solvent mixture containing systematically varied amounts of methyl isobutyl ketone (MIBK) in deuterated cyclohexane was studied using FT-IR imaging. From each sequential image in a timed sequence, spatially resolved spectral data were gathered and absorbance profiles for the field of view were obtained. This allowed the study of solvent penetration and quantitative analysis of the dissolution process from concentration profiles. The dissolution of the polymer was found to vary linearly with time for similar to 150 mum dissolved layer. The dissolution rate was found to increase linearly with MIBK concentration. In each solvent mixture, diffusion profiles were characteristic of case LI diffusion. No solvent component segregation was seen. It is demonstrated that PT-IR imaging is a viable tool to characterize the dissolution of polymers by multicomponent solvents.