FOURIER-TRANSFORM NEAR-INFRARED MONITORING OF REACTING RESINS USING AN EVANESCENT-WAVE HIGH-INDEX FIBEROPTIC SENSOR

In this work, a high-index silica-based fiber-optic mini-bundle sensor was constructed and implemented with a Fourier transform near-infrare d spectrometer in the spectral region from 10 000 to 4500 cm(-1). The refractive index of the multimode step index fiber was 1.618. This arr angement allows the propagation of waveguiding modes when the sensor i s immersed in most resin systems. The reactions of a polyisocyanurate resin system and an epoxy resin system were monitored and peak assignm ents were made and discussed with respect to their potential for use i n real-lime analysis to he applied to cure control. Last, cure monitor ing with this sensor was successfully demonstrated in a glass-reinforc ed resin transfer molded epoxy part.