Method of making titania-doped fused silica

Claim 1

In a method for making a non-porous body of high purity fused silica glass doped with titania comprising the steps of: (a) producing a gas stream containing a silicon-containing compound in vapor form capable of being converted through thermal decomposition with oxidation or flame hydrolysis to SiO 2 and a titanium-containing compound in vapor form capable of being converted through thermal decomposition with oxidation or flame hydrolysis to TiO 2; (b) passing said gas stream into the flame of a combustion burner to form amorphous particles of fused SiO 2 doped with TiO 2 and containing submicroscopic crystals of rutile and anatase with rutile being the predominant crystal phase; (c) depositing said amorphous particles onto a support; and (d) either essentially simultaneously with said deposition or subsequently thereto consolidating said deposit of amorphous particles into a non-porous body; the improvement comprising utilizing as said titanium-containing compound in vapor form a halide-free, titanium-containing compound selected from the group consisting of titanium-2-ethylhexyloxide, titanium cyclopentyloxide, and a titanium amide, or a combination thereof, whereby no halide-containing vapors are emitted from said titanium-containing compound during the making of said porous body.