Refractive index of silica glass: influence of fictive temperature

The refractive index (RI) and the peak position of the first overtone of th e fundamental SiO4-tetrahedron vibration mode, 2 nu(3), have been studied a s a function of fictive temperature. The materials used are synthetic silic a glasses of type III (trade names: F310, F300 and F320), which contain mai nly hydroxyl, chlorine and fluorine, respectively, and one natural silica g lass of type II (trade name: Heralux-WG). Two main results are presented: ( 1) The dependence of the RI on the fictive temperature is described for the different types of silica glass; (2) It is shown that the IR-absorption da ta can be used to determine the fictive temperature of silica glass. In bot h cases the four silica glasses behave differently because of the different types of dopants and dopant concentrations. (C) 2000 Elsevier Science B.V. All rights reserved.