Patent ID: 11932573
Assignee: SCHOTT AG
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  A  G  H | IPC A  C  G  H

Claim 21:
22. An element comprising:
glass having a surface and interior, the glass comprising at least one alkali metal and/or an alkali metal oxide,
wherein the glass comprises, at a distance of at least 50 nanometers measured perpendicularly from the surface, the following proportions in percent by weight on an oxide basis:
silicon dioxide (SiO2) from 50 to 77 percent,
aluminum oxide (Al2O3) from 0.5 to 7 percent,
boron trioxide (B2O3) from 0.1 to 8 percent,
iron(III) oxide (Fe2O3) from 0 to 8 percent,
sodium oxide (Na2O) from 0 to 18 percent,
potassium oxide (K2O) from 0 to 17 percent,
lithium oxide (Li2O) from 0 to 6 percent,
wherein the glass has a concentration of the at least one alkali metal and/or the alkali metal oxide that increases from the surface in a direction of the interior in such a way that a maximum concentration of the at least one alkali metal and/or an alkali metal oxide is present at a distance of not more than 60 nanometers measured perpendicularly from the surface, and
wherein the combined total oxides of Ca, Mg, Ba, Sr and Zn is from 3.5 to 17 percent.