The uptake of small solvent molecules by polymers via diffusion or other transport mechanisms plays an important role in many technical applications. The transport can be described by the evolution of the concentration profile. These profiles are also the basis for quantitative models and a deeper understanding of the underlying processes. Here, the capabilities of a novel Raman imaging technique, femtosecond stimulated Raman microscopy (FSRM), are illustrated in a study on the uptake of methanol by poly(methyl methacrylate). With FSRM, concentration profiles of methanol with a spatial resolution of about 1 itm are obtained. Recording of a complete Raman spectrum for one pixel takes 10 ms, allowing us to investigate reasonably big areas with a temporal resolution of minutes. The profiles feature sharp concentration drops, which find their counterpart in optical images. The measured profiles are quantitatively compared with theoretical predictions.