Ultra-low expansion silica-titania glasses are produced by flame deposition of a mixture of vaporized octamethylcyclotetrasiloxane (OMCTS) and vaporized titanium isopropoxide (Ti-Ipox).

Such a precipitate if allowed to form will result in premature shutdown of the glass making process and can result in undesirable variations in the composition of the silica-titania glass being produced.

The titania photocatalyst contains a brookite crystal phase.

Still further, there is provided a product comprising the above titania photocatalyst.

The beads are based on a tetravalent metal oxide, such as zirconia, titania or hafnia.

The abrasive particles can be alumina, zirconia, silica, titania or combinations of the foregoing.

Optionally zirconia and/or titania may be added to the composition to further improve alkali resistance.