In this work, the kinetics of microemulsion copolymerization of styrene (St) and methyl methacrylate (MMA) at 60 degrees C using dodecyltrimethylammonium bromide (DTAB) as the surfactant was followed on line by low-resolution Raman spectroscopy. Raman spectra were taken every 30 s. Because the spectrophotometer has low resolution, the C=C peak overlaps with the St aromatic ring stretch vibration and curve deconvolution was necessary. Overall conversion obtained by Raman spectroscopy agrees with that obtained by gravimetry. Copolymer composition was determined by following the area changes of the C-O-C bending mode peak of MMA. Compositions determined by this method agree with those measured by NMR spectroscopy. POLYM. ENG. SCL, 49:2125-2131, 2009. (C) 2009 Society of Plastics Engineers