Titania-silica glass with uniform hydroxyl concentration

A process of forming a titania-silica glass body, the process comprising:

• exposing a titania-silica soot body to a first thermal treatment by heating the body to a first temperature T1 between about 800° C. and about 1100° C. for a first time duration t1 calculated using the equation:
• t
• ⁢
• 1
• >
• L
• c
• 2
• 4
• ⁢
• α
• wherein Lc is a length (cm) of the body and a is the thermal diffusivity (cm2/sec) of the body;
• increasing the temperature of the body from the first temperature T1 to a second temperature T2 at a rate of about 20° C./hour or greater;
• and
• exposing the body to a second thermal treatment by heating the body at the second temperature T2 between about 1050° C. and about 1250° C. for a second time duration t2 such that the second temperature T2 is greater than the first temperature T1,
• wherein, after the second thermal treatment, a peak-to-valley difference of hydroxyl concentration amongst a plurality of segments of the body is about 70 ppm or less, the hydroxyl concentration being measured using a Fourier transform infrared spectroscopy in transmission, and the plurality of segments includes every adjacent segment across a specific length and a specific width of the body, the specific length being about 25 mm or more and the specific width being about 25 mm or more.