Structural Study of Quartz Glasses Doped with Fluorine by ¹⁹F-NMR

Abstract

The chemical structures of fluorine doped into two types of quartz glasses synthesized by CVD method were examined with a high resolution ¹⁹F-NMR spectrometer. Longitudinal relaxation times (T₁) of the fluorine in SiO₂: F glasses were seven times longer than those in the glasses doped with boron and fluorine. Though the difference of the chemical shifts was slight (-3ppm), fluorine nuclei in SiO₂: F glasses were shifted downfield from those in SiO₂: B: F glasses. Therefore, the environments of fluorine nuclei in the two types of glasses were considerably different. It was suggested that the fluorine was probably bonded to the boron in SiO₂: B: F glasses, while the fluorine was bonded to the silicon in SiO₂: F glasses.