Reverse photochromic borosilicate glasses

Patent metadata

Field	Value
Publication number	US-9527769-B2
Application number	US-201414508548-A
Country	US
Kind code	B2
Filing date	Oct 7, 2014
Priority date	Oct 9, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

Borosilicate glasses are disclosed having (in weight %) 66-76% SiO 2 , 0-8% Al 2 O 3 , 10-18% B 2 O 3 , 0-4% Li 2 O, 0-12% Na 2 O, 0-12% K 2 O, 1-1.5% Ag, 1.5-2.5% Cl − and 0.01-0.06% of a summed amount of CuO and NiO, wherein the glass composition is bleachable upon exposure to ultraviolet irradiation from a stable state color or shade to a lighter color or shade. Such reverse photochromic borosilicate glass compositions may be thermally darkenable. The borosilicate glasses may be strengthened via ion-exchange strengthening treatment. The borosilicate glasses may retain their reverse photochromic and thermally darkenable properties even after ion-exchange strengthening treatment.

First claim

What is claimed is:

1. A photochromic borosilicate glass composition comprising (in weight %) 66-76% SiO 2 , 0-8% Al 2 O 3 , 10-18% B 2 O 3 , 0-4% Li 2 O, 0-12% Na 2 O, 0-12% K 2 O, 1-1.5% Ag, 1.5-2.5% Cl − and 0.01-0.06% of a summed amount of CuO and NiO, wherein the glass composition is bleachable upon exposure to ultraviolet irradiation from a stable state color or shade to a lighter color or shade.

2. The photochromic borosilicate glass composition of claim 1 wherein the glass is thermally darkenable.

3. The photochromic borosilicate glass composition of claim 2 wherein the glass composition is thermally darkenable at a temperature of 150° C. or greater.

4. The photochromic borosilicate glass composition of claim 1 comprising 2-12% Na 2 O.

5. The photochromic borosilicate glass composition of claim 1 which is substantially free of at least one of Li 2 O or Br − .

6. The photochromic borosilicate glass composition of claim 1 comprising 2-8% Al 2 O 3 , 4-12% Na 2 O and 0-6% K 2 O, wherein the weight % of Na 2 O is greater than the weight % of K 2 O.

7. The photochromic borosilicate glass of claim 6 which is substantially free of at least one of Li 2 O or Br − .

8. The photochromic borosilicate glass composition of claim 1 comprising 68.6-71.6% SiO 2 , 3-6% Al 2 O 3 , 13.4% B 2 O 3 , 4.5-9% Na 2 O, 0-4.5% K 2 O, 1.2% Ag, 1.8% Cl − and 0.03% CuO, wherein the weight % of Na 2 O is greater than the weight % of K 2 O and the composition is substantially free of Li 2 O and Br − .

9. The photochromic borosilicate glass composition of claim 1 wherein immersion of the photochromic borosilicate glass composition in a molten salt bath for a predetermined time and temperature causes ion-exchange.

10. A multi-layer glass laminate comprising a substrate layer and at least one photochromic borosilicate glass layer comprising the photochromic borosilicate glass composition of claim 1 .

11. A multi-layer glass laminate comprising a substrate layer and a photochromic borosilicate glass layer disposed on both sides of the substrate layer and comprising the photochromic borosilicate glass composition of claim 1 .

12. A multi-layer glass laminate, wherein one or more layers of the multi-layer glass laminate comprises the photochromic borosilicate glass composition of claim 1 .

13. A photochromic borosilicate glass composition, which when exposed to ultraviolet irradiation exhibits a lightening in color or shade and is thermally darkenable, the photochromic borosilicate glass composition comprising (in weight %) 66-76% SiO 2 , 2-8% Al 2 O 3 , 10-18% B 2 O 3 , 0-4% Li 2 O, 2-12% Na 2 O, 0-12% K 2 O, 1-1.5% Ag, 1.5-2.5% Cl − and 0.01-0.06% of a summed amount of CuO and NiO, wherein the photochromic borosilicate glass composition is substantially free of Br − .

14. The photochromic borosilicate glass composition of claim 13 comprising 1.2% Ag and 1.8% C − .

15. The photochromic borosilicate glass composition of claim 13 comprising 13.4% B 2 O 3 .

16. The photochromic borosilicate glass composition of claim 13 which is substantially free of Li 2 O.

17. The photochromic borosilicate glass composition of claim 13 comprising 6% Al 2 O 3 , 13.4% B 2 O 3 , 4.5% Na 2 O, 1.2% Ag, 1.8% Cl − and 0.03% CuO.

18. The photochromic borosilicate glass composition of claim 13 comprising 6% Al 2 O 3 , 13.4% B 2 O 3 , 9% Na 2 O, 1.2% Ag, 1.8% Cl − and 0.03% CuO, wherein the composition is substantially free of K 2 O.

19. The photochromic borosilicate glass composition of claim 13 comprising 3% Al 2 O 3 , 13.4% B 2 O 3 , 3% K 2 O, 6% Na 2 O, 1.2% Ag, 1.8% Cl − and 0.03% CuO.

20. A method of strengthening a glass composition comprising: immersing in a molten salt bath a photochromic borosilicate glass composition comprising (in weight %) 66-76% SiO 2 , 2-8% Al 2 O 3 , 10-18% B 2 O 3, 0-4% Li 2 O, 2-12% Na 2 O, 0-12% K 2 O, 1-1.5% Ag, 1.5-2.5% Cl − and 0.01-0.06% of a summed amount of CuO and NiO, wherein the photochromic borosilicate glass composition is bleachable upon exposure to ultraviolet irradiation from a stable state color or shade to a lighter color or shade, and wherein the photochromic borosilicate glass composition is immersed in the molten salt bath for a time and at a temperature sufficient to cause ion-exchange.

Assignees

• Corning Inc

Inventors

• Mauro John Christopher
• Thirion Lynn Marie

Classifications

• C03C17/02

  with glass (C03C17/34, C03C17/44 take precedence) · CPC title

• C03C2204/04

  Opaque glass, glaze or enamel · CPC title

• C03C8/06

  containing halogen · CPC title

• C03C3/089

  containing boron · CPC title

• C03C8/02

  Frit compositions, i.e. in a powdered or comminuted form · CPC title