IDENTIFICATION METHOD FOR INFRARED-ABSORPTION SPECTRA OF SEMITRANSPARENT MEDIA BY THEIR EMISSION DATA APPLICATION TO LIME-ALUMINOSILICATE GLASSES AT HIGH-TEMPERATURES

The infrared absorption spectra of four lime-aluminosilicate glasses h ave been studied at high temperatures in the spectral range 1 to 5 mum . The glass composition varies essentially by the FeO content. The eff ect of temperature is pointed out up to 1450-degrees-C. The emission s pectrometry technique used is applied to thin slabs of semitransparent materials heated in plane-parallel platinum crucibles exposed to stro ng temperature gradients. The absorption coefficient is identified, fo r each wavelength, by a non-linear constraint optimization technique. As an illustration of the major influence of the spectrum on the heat exchanges in semitransparent devices, a modeling of the combined condu ctive/radiative heat transfer is performed in a glass wall.