Process for measurement of the degree of cure and percent resin of glass- fiber reinforced epoxy resin prepreg

摘要

The degree of cure and the amount of epoxy resin in a glass fiber reinforced epoxy resin prepreg is measured by exposing the prepreg to a series of light pulses created by optical filters transmitting light at predetermined bandwidths about selected wavelengths, preferably centered at wavenumbers of about 4529 cm.sup.-1 and 4055 cm.sup.-1 and measuring the amount of epoxy groups and methyl groups present relative to reference values from the electrical pulses produced by a phase sensitive photoelectric detector disposed to receive said light pulses after being exposed to said prepreg. When such measurements are made in a continuously moving sheet of prepreg, it is possible to control the variation of percent cure and resin content to no greater than .+-.3% cure and .+-.3% resin content over a distance of at least 400 yds (366 m).