Method for improving the chemical durability of opal glasses
Abstract
Abstract THE PRESENT INVENTION RELATES TO A PROCESS FOR IMPROVING THE CHEMICAL DURABILITY OF GLASS ARTICLES AND, PARTICULARLY, TO A THERMAL TREATMENT WHICH MODIFIES A THIN SURFACE LAYER ON GLASS ARTICLES THAT ARE OPAL BECAUSE OF PHASE SEPARATION THEREIN IN SUCH A MANNER THAT THE PHENOMENON OF PHASE SEPARATION US SUPPRESSED OR CONTROLLED WITHIN THIS THIN SURFACE LAYER, WHEREAS, AT THE SAME TIME, THE INTERIOR GLASS IS ALLOWED TO ATTAIN OR RETAIN THE DEGREE OF PHASE SEPARATION WHICH IS NECESSARY TO OBTAIN THE DESIRED OPALESCENCE. THIS PROCESS IS OF SPECIAL INTEREST FOR PRODUCTS FORMED FROM GLASSES WITH IMMISCIBLE VITREOUS PHASE WHICH ARE LIKELY TO BE EXPOSED, DURING USE, TO THE ACTION OF RELATIVELY REACTIVE CHEMICAL SOLUTIONS SUCH AS WATER, ACIDS, ALKALINE WASH WATERS, OR PHOSPHATE WASH WATERS.
Inventors
- 👤 A Andrieu
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |