Effect of oxygen content on formation of defect in pure quartz glass

The present report deals with the dependence of the formation of various defects on the oxygen content in glass. For 13 fiber samples, each consisting of a pure quartz core and silicone clad, the OH content is determined from the absorption of 950 nm light, and the chlorine content is measured by activation analysis and XMA. In addition, three material samples are prepared by changing the gas flow rate during the plasma process for glass production. The samples are irradiated with γ-ray and subjected to treatment with heated oxygen gas or heated helium gas (600 deg C, 2 atm) for 24 hours. Observations are made to determine the ESR spectra, effects of oxygen content on the optical absorption at 245 nm, relations of the 2 eV-absorption intensity with the terminator density, and dependence of photoconduction on wavelength. Results show that some silica fibers contain an excess amount of oxygen while others has an inefficient oxygen content, and that the total content of oxygen has close relations with the 245 nm band as well as the formation of various drawing-induced defects and γ-ray-induced peroxy radicals. It is also revealed that the 245 nm band seems to result from the formation of the Si-Si bond due to a lack of oxygen. (Nogami, K.)