US4043781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making a brown photochromic glass
Assignee: Corning Glass Works
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Filing: 1976-05-24
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Granted: 1977-08-23
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Expires: 1996-05-24
Abstract
Abstract A silver-halide photochromic glass of alkali-boroaluminosilicate base composition, having a brown coloration in the faded and darkened state, is provided by treating a potentially photochromic glass of specified composition according to a defined two-phase heat treatment to develop photochromic properties therein.
Inventors
- 👤 Clark V. DeMunn
- 👤 David J. Kerko
- 👤 Ralph A. Westwig
- 👤 David B. Wrisley, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:21
CPC Classifications
C; C03; C03C; C03C4/00; C03C4/04; C03C4/06; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
173 words
A method for making a photochromic glass article having a brown coloration in the faded and darkened state which comprises a. providing a potentially photochromic glass article having a composition consisting essentially, in weight percent, of about 53-60% SiO 2 , 8-10% Al 2 O 3 , 15-18% B 2 O 3 , 1-3% Na 2 O, 1.5-3.2% Li 2 O, 5-9% BaO, 3.5-7% PbO, 0-4% ZrO 2 , 0.012-0.040% CuO, 0.14-0.22% Ag, 0.22-0.36% Cl, 0.10-0.20% Br and 0-1% F; b. heating the potentially photochromic glass article to a temperature in the temperature range of about 520°-580° C., and maintaining the article in that temperature range for a time of about 2-30 minutes; c. further heating the potentially photochromic glass article to a temperature in the temperature range of about 600°-660° C. and maintaining the article in that temperature range for a time of about 5-60 minutes; and d. cooling the article to room temperature; said brown coloration resulting from said method being present throughout the entire volume of said photochromic glass article.
Claim 2
Independent Claim
173 words
A method for making a photochromic glass article having a brown coloration in the faded and darkened state which comprises a. providing a potentially photochromic glass article having a composition consisting essentially, in weight percent, of about 53-60% SiO 2 , 8-10% Al 2 O 3 , 15-18% B 2 O 3 , 1-3% Na 2 O, 1.5-3.2% Li 2 O, 5-9% BaO, 3.5-7% PbO, 0-4% ZrO 2 , 0.012-0.040% CuO, 0.14-0.22% Ag, 0.22-0.36% Cl, 0.10-0.20% Br and 0-1% F; b. heating the potentially photochromic glass article to a temperature in the temperature range of about 520°-580° C., and maintaining the article in that temperature range for a time of about 2-30 minutes; c. further heating the potentially photochromic glass article to a temperature in the temperature range of about 600°-660° C. and maintaining the article in that temperature range for a time of about 5-60 minutes; and d. cooling the article to room temperature; said brown coloration resulting from said method being present throughout the entire volume of said photochromic glass article.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-22 | 1981-02-21 | 1981-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-22 | 1985-02-21 | 1985-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-22 | 1989-02-21 | 1989-08-23 | $7700.00 | Window Closed / Lapsed |