Four-band fiber optic radiometry for true temperature measurements during an exothermal process

Four-band fiber optic radiometry is a method for noncontact temperature measurement of a sample with an unknown emissivity, assuming the emissivity is uniform in all four spectral bands. The method corrects the temperature calculation automatically, according to the emissivity calculation, during continuous measurements on the sample. This method may be particularly useful in determining the temperature of a material that undergoes a transition in which both temperature and emissivity change, such as phase transitions or exothermic processes. We report a radiometric four-band measurement in the mid-infrared region, for determining the true temperature of an epoxy resin during its curing.