The dissolution process of poly(methyl methacrylate) in mixtures of methanol and carbon tetrachloride, individually nonsolvents for the polymer (under the conditions of study), was studied at 25 degreesC using FTIR imaging spectroscopy. To investigate this cosolvency phenomenon, the spatial resolution and sensitivity of FTIR imaging to interactions between the components were used. The results obtained suggest that the dissolution process of the PMMA in a high weight fraction of the CCl4/CH3OD solvent mixtures consists of first the swelling of the PMMA by the CCl4 allowing the methanol to penetrate into the PMMA and specifically interact (hydroxyl-carbonyl hydrogen bonds) with the polymer to separate the polymer chains. Furthermore, the effect of compositions of the solvent mixtures on the dissolution rates is a result of two opposite effects: (i) the ability of the polymer to be swelled (CCl4 fraction) and (ii) the number of specific interactions between the polymer and one of the nonsolvents (methanol fraction).