Monitoring of cure‐induced strain of an epoxy resin by fiber Bragg grating sensor

In this study, we present a method to detect cure-induced strain in an epoxy resin (EP) with a Fiber Bragg Grating (FBG) sensor. By embedding the opti- cal fiber into the EP resin the characteristics during iso- thermal cure (gel point, vitrification) could be precisely detected due to changes in the fiber strain. In a follow up dynamic temperature scan the coefficient of thermal expansion and the glass transition temperature (Tg) of the fully cured EP were determined by the FBG sensor tech- nique. All results obtained by the fiber optical method showed a very good agreement with those deduced by independent techniques, viz. rheological measurements, differential scanning calorimetry, and thermomechanical analysis. 2007 Wiley Periodicals, Inc. J Appl Polym Sci 107: 719-725, 2008