REMOTE RAMAN-SPECTROSCOPY AS A SENSOR TECHNOLOGY IN COMPOSITE-MATERIALS PROCESSING

This paper describes the development and application of fiber-optic Ra man spectroscopy as a probe of the physicochemical properties of compo site materials. The construction of a Fourier transform near-infrared Raman spectrometer is described with special attention to the efficien t implementation of fiber-optic sensors. This instrument has been inte rfaced with a processing autoclave and allows, for the first time, the in-situ measurement of molecular vibrational spectra in the fundament al over long (similar to 100 m) distances. Spectral performance has be en assessed by measuring the Raman spectra of a number of well-charact erized organic species using the fiber-optic sensor and following the cure kinetics of an epoxy resin. This type of fiber-optic sensor is sm all and essentially non-invasive (100-550 micron diameter) and can ser ve the dual purpose of providing useful sensor information for materia ls and processing operations in manufacturing and can be left in place to serve as a monitor of the integrity during the lifetime of detail components or major assemblies