Spectral Remote Sensing of Temperature Distribution in Glass

A numerical method is developed for recovering the temperature distribution in glass from spectral radiation emission data. The desired temperature distribution is obtained using an optimization scheme that determines the best temperature profile from the data in a form of discrete points or Legendre polynomials. In order to evaluate the accuracy and validity of the spectral remote sensing method, the recovered temperatures are compared with independent measurements in two different experiments, one of which uses a Mach-Zehnder interferometer. Experimental results are reported for Corning Code 7940 fused silica using a Perkin-Eimer spectrometer to measure the spectral radiant energy emerging from the glass. The recovered and interferometrically measured temperatures are found to be in good agreement, i.e., within about 1 ¿ percent at temperatures up to about 800 K.