Ultralow expansion titania-silica glass

Patent metadata

Field	Value
Publication number	US-10329184-B2
Application number	US-201715686313-A
Country	US
Kind code	B2
Filing date	Aug 25, 2017
Priority date	Feb 13, 2015
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

Annealing treatments for modified titania-silica glasses and the glasses produced by the annealing treatments. The annealing treatments include an isothermal hold that facilitates equalization of non-uniformities in fictive temperature caused by non-uniformities in modifier concentration in the glasses. The annealing treatments may also include heating the glass to a higher temperature following the isothermal hold and holding the glass at that temperature for several hours. Glasses produced by the annealing treatments exhibit high spatial uniformity of CTE, CTE slope, and fictive temperature, including in the presence of a spatially non-uniform concentration of modifier.

First claim

What is claimed is:

1. A method of annealing glass comprising:
heating a modified titania-silica glass to a first temperature, said modified titania-silica glass including a non-uniform concentration of a modifier, said first temperature exceeding 850° C.;
cooling said modified titania-silica glass at a first cooling rate from said first temperature to a second temperature, said second temperature being in the range from 650° C. to 800° C.; and
holding said modified titania-silica glass at said second temperature for a first time period, said first time period lasting for at least 10 hours.

2. The method of claim 1 , wherein said modifier is F or B 2 O 3 .

3. The method of claim 1 , wherein said non-uniform modifier concentration includes a peak-to-valley variation of at least 0.10 wt %.

4. The method of claim 1 , wherein said first cooling rate is 1° C./hr or greater.

5. The method of claim 1 , further comprising cooling said modified titania-silica glass at a second cooling rate from said second temperature to a third temperature, said second cooling rate exceeding 50° C./hr and said third temperature being at least 300° C. less than said second temperature.

6. The method of claim 1 , further comprising heating said modified titania-silica glass from said second temperature to a third temperature, said third temperature exceeding said second temperature by no more than 25° C.

7. The method of claim 6 , further comprising holding said modified titania-silica glass at said third temperature for a second period of time, said second period of time lasting at least 5 hours.

Assignees

• Corning Inc

Inventors

• Annamalai Sezhian
• Duran Carlos Alberto
• Hrdina Kenneth Edward
• Rosch William Rogers

Classifications

• C03C2201/14

  containing boron and fluorine · CPC title

• C03C3/089

  containing boron · CPC title

• C03C2201/12

  containing fluorine (C03C2201/14 takes precedence) · CPC title

• C03B2201/10

  doped with boron (C03B2201/14 takes precedence) · CPC title

• C03B19/1453

  Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering · CPC title