In this study, near-infrared transmission spectroscopy is investigated as an alternative technique for the real-time cure monitoring of thermosets systems. Two polymer systems based on dimethacrylate/styrene and dimethacrylate/divinylbenzene monomers were studied in order to check the influence of comonomer functionality. A new device utilizing ITO (indium-tin-oxide)-coated glass plates was developed to take into account the specificity of chain polymerization: oxygen inhibition, bulk polymerization, etc. Two absorption bands at 6166 and 6135 cm<sup>-1</sup> suitable for <i>in situ</i> monitoring of methacrylate and vinyl double bonds were identified, and the molar absorption coefficient was determined. A quantitative analysis allows us to calculate the double-bond conversion during the polymerization in isothermal conditions between 60 and 80 °C.
L. Rey, J. Galy, H. Sautereau, G. Lachenal, D. Henry, and J. Vial, "Near-Infrared Spectroscopy for in Situ Cure Monitoring of Dimethacrylate-Based Networks," Appl. Spectrosc. 54, 39-43 (2000)