Refractive index of silica glass: influence of fictive temperature

The refractive index (RI) and the peak position of the first overtone of the fundamental SiO4-tetrahedron vibration mode, 2ν3, have been studied as a function of fictive temperature. The materials used are synthetic silica glasses of type III (trade names: F310, F300 and F320), which contain mainly hydroxyl, chlorine and fluorine, respectively, and one natural silica glass 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 data can be used to determine the fictive temperature of silica glass. In both cases the four silica glasses behave differently because of the different types of dopants and dopant concentrations.