Fourier transform Raman spectroscopy near-infrared (NIR) laser excitation was used to follow an emulsion polymerization reaction involving methyl methacrylate, butyl acrylate and allyl methacrylate monomers in a water continuous phase. The effect of NIR absorption is discussed in relation to the monomers and water. For the system studied, only parts of the spectrum are shown to suffer from significant self-absorption due to the water. Fortunately, for monitoring the polymerization reaction through the loss in the band due to the symmetric C=C stretch, self-absorption is shown not to play a significant role.
