摘要 |
1. Glass vessel, especially an ampoule, having a pretension generated at a specific site, said pretension allowing the opening of this vessel at this site after scratching by means of a suitable tool, characterized in that said pretension has exclusively been generated by thermal treating of the vessel without having been touched by a tool and that it shows a tension profile at which a tensile strain ring being generated first and going around the periphery of the glass vessel is superimposed at one site (1) by a punctuate compressive strain zone being generated later. |