Cure monitoring of epoxy resin via use of FBG

In order to monitor curing process of epoxy resin, the special system was established based on Fiber Bragg Grating (FBG). A bare FBG, a FBG packaged with quartz capillary and an accurate resistance thermometer were immersed into mixture of epoxy resin and curing agent, and were used to monitoring the whole curing process. The changes of temperature inside epoxy resin were detected by resistance thermometer. Meanwhile, the reflection wavelengths of two Fiber Bragg Gratings were measured by spectrum analyzer. Experimental results indicate that the temperature evolution monitored by FBG packaged into quartz capillary is the same as measurement results of resistance thermometer. During curing process, inner strain changes of epoxy resin can be taken in by the variation of wavelength difference of two FBGs. At the beginning of polymerization reaction, the strain inside epoxy resin quickly increases, and then gradually trends to constant value. The temperature and shrinkage strain monitor of epoxy resin has been implemented via using FBG. It is a new approach to monitor curing process of polymer materials.