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

Claim 20:
21. 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 and Sr is from 0 to 15 percent.