COMPARATIVE-STUDY OF INCORPORATION OF CL AND F INTO SIO2 DURING THE MCVD PROCESS

We report the results of examination of incorporation of chlorine and fluorine into silica as revealed from secondary ion mass spectroscopy (SIMS) and Raman spectroscopy measurements. The samples were preform-l ike rods made by the MCVD process. SIMS spectra were used for quantita tive analysis of Cl concentration in glass. The concentrations of F we re obtained from the Raman spectra. Both spectroscopic methods indicat ed the presence of Si-Cl groups in SiO2 synthesized from chlorine-rich vapour gaseous blend. The difference in structural roles of Cl and F in chemically deposited silica manifests itself in the efficiency of t heir bonding to Si and in interaction with intrinsic structural defect s.