TEMPERATURE-DEPENDENCE OF THE OH- ABSORPTION IN SIO2 GLASS AND MELT TO 1975K

FTIR absorbance spectra of SiO2 glass containing 1200 ppm OH- groups w ere recorded in situ to 1975 K. There are only minor changes in peak h eight to 1700 K, indicating that the molar extinction coefficient meas ured at ambient conditions, at the peak maximum, is applicable for OH- determination at high temperature. However the integrated peak intens ity shows a slight decrease with increasing temperature over the entir e temperature range, due to changes in the band shape associated with small modifications to the hydrogen bonding environment and loss of hy drous component at the highest temperatures.