Raman spectroscopy on SiO2 glasses sintered from nanosized particles

The forming and sintering of fumed silica powders is an interesting route for the preparation of large, pure or doped silica glasses with precise geometry. Here we have investigated the process of sintering of transparent silica glass by Raman spectroscopy. The main changes in the Raman spectra appeared in the range of defects bands D1 and D2. The process of sintering in oxygen, hydrogen, helium and water vapour as well as by crystallization and remelting has been monitored by the changes in amplitudes of defect bands. The results were analyzed in the small planar ring and the paracrystalline cluster interface models.