# US 2014/0151613 A1 · Photochromic glasses

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- Number: US 2014/0151613 A1
- Document ID: US20140151613A1
- Status: Published application
- Kind: A1
- Application number: 14/071,851
- Filed: 2013-11-05
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Corning Incorporated
- Applicants: Corning Incorporated
- Inventors: Yves Andre Henri Brocheton
- Web page: https://patentgrep.com/patent/US20140151613A1

## CPC

- C03C 3/093: containing zinc or zirconium
- C03C 3/097: containing phosphorus, niobium or tantalum
- C03C 4/06: for phototropic or photochromic glass
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

Described herein are photochromic glasses that are at least substantially free of rare earth elements. Methods of making and using the photochromic glasses are also described.

## Claims

### Claim 1

A photochromic glass, comprising:
a glass matrix that is at least substantially free of rare earth elements, comprising in weight percent (wt %) based on oxides:
48 wt %≦SiO2≦58 wt %;
15 wt %≦B2O3≦21 wt %;
5 wt %≦Al2O3≦9 wt %;
2.5 wt %≦ZrO2≦6.5 wt %;
2 wt %≦Li2O≦4 wt %;
0 wt %≦Na2O≦3 wt %;
3 wt %≦K2O≦10 wt %;
0 wt %≦MgO≦2 wt %;
0 wt %≦CaO≦2 wt %;
0 wt %≦SrO≦2 wt %;
0 wt %≦BaO≦2 wt %;
0 wt %≦TiO2≦2.5 wt %;
2 wt %≦Nb2O5≦4.5 wt %; and
a plurality of photochromic agents, comprising in weight percent (wt %) with respect to the glass matrix:
0.100 wt %≦Ag≦0.250 wt %;
0.200 wt %≦Cl≦0.500 wt %;
0.0100 wt %≦Br≦0.300 wt %; and
0.0050 wt %≦CuO≦0.0110 wt %

### Claim 2 (depends on 1)

The photochromic glass of claim 1, wherein the plurality of photochromic agents further comprise a reducing agent, which can be Sb2O3 and/or SnO2, in an amount up to about 0.5 wt %.

### Claim 3 (depends on 1)

The photochromic glass of claim 1, wherein the photochromic glass is at least substantially free of TiO2.

### Claim 4 (depends on 1)

The photochromic glass of claim 1, wherein the photochromic glass is at least substantially free of alkaline-earth oxides.

### Claim 5 (depends on 1)

The photochromic glass of claim 1, wherein the photochromic glass is at least substantially free of TiO2 and alkaline-earth oxides.

### Claim 6 (depends on 1)

The photochromic glass of claim 1, wherein the photochromic glass exhibits at least one of the following properties:
a transmission in the clear state T0>86%;
transmission in the darkened state after a 15 minute exposure to a solar simulator at 22° C. (Td15—22C)<35%;
transmission in the darkened state after a 15 minute exposure to a solar simulator at 35° C. (Td15—35C)<45%; or
fast fading characterized by a transmission Tf5 (5 minutes after UV extinction)>45%.

### Claim 7 (depends on 1)

A lens, comprising the photochromic glass of claim 1.