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Fourier transform infrared (FTIR) fiber optic monitoring of composites during cure in an autoclaveReal-time in situ monitoring of the chemical states of epoxy resins was investigated during cure in an autoclave using infrared evanescent spectroscopy. Fiber evanescent sensors were developed which may be sandwiched between the plies of the prepreg sample. A short length of sapphire fiber was used as the sensor cell portion of the fiber probe. Heavy metal fluoride glass optical fiber cables were designed for connecting the FTIR spectrometer to the sensor fiber within the autoclave. The sapphire fibers have outstanding mechanical thermal properties which should permit their use as an embedded link in all thermoset composites. The system is capable of operation at a temperature of 250 C for periods up to 8 hours without major changes to the fiber transmission. A discussion of the selection of suitable sensor fibers, the construction of a fiber-optic interface, and the interpretation of in situ infrared spectra of the curing process is presented.
Document ID
Document Type
Conference Paper
Druy, Mark A. (Foster-Miller Associates, Inc. Waltham, MA, United States)
Elandjian, Lucy (Foster-Miller Associates, Inc. Waltham, MA, United States)
Stevenson, William A. (Foster-Miller Associates, Inc. Waltham, MA, United States)
Driver, Richard D. (Foster-Miller Associates, Inc. Waltham, MA, United States)
Leskowitz, Garett M. (IRIS Fiber Optics, Inc. Acton, MA, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1990
Subject Category
Distribution Limits