FLUORINE INCORPORATION IN SILICA GLASS BY MCVD PROCESS - A CRITICAL-STUDY

The chemistry of fluorine incorporation in silica glass preparatory to preform fabrication by MCVD process was critically analysed on the ba sis of the thermodynamic properties of the constituent reagents. The t heoretical findings were compared with the experimental results, point ing out the anomalies observed by different workers. The addition of p hosphorus is found to have an insignificant role in modifying the fluo rine incorporation level. The accepted model of dependence of fluorine content in the glass on the partial pressure of SiF4 to the power of 0.25 finds poor agreement with the experimental data at low fluorine d opant concentration.