The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 31, 1981
Filed:
May. 05, 1980
Werner Sack, Mainz, DE;
Jenaer Glaswerk Schott & Gen., Mainz, DE;
Abstract
Glass compositions have been found which, with a low linear thermal expansion coefficient of 33.9-53.2.times.10.sup.-7 /.degree.C. at 20-300.degree. C. will pre-stress to a much higher extent under similar prestressing conditions than known glasses of the same thermal expansion, and which consequently result in crumbling under forced fracture. The glasses possess the following properties: the transformation temperatures (Tg) are between 566.degree. and 660.degree. C., the softening temperatures (Ew) are between 821.degree. and 845.degree. C. and working temperatures are between 1211.degree. and 1370.degree. C., the temperature differential Ew-Tg being 232.degree. to 298.degree. C., the ratio .alpha.'/.alpha. of the thermal expansion coefficient above Tg (.alpha.') to expansion below Tg (.alpha.) being between 4.1 and 9.4 and the formation comprising: