Apparatus and method for thermally treating an annular region of an inner surface of a glass container produced from a borosilicate glass tube

A method for thermally treating an annular region of an inner surface of a borosilicate glass container,

• wherein the glass container comprises a glass tube having a longitudinal axis, a first end of the glass tube, and a second end of the glass tube,
• the method comprising the steps of:
• forming a bottom of the glass container on the glass tube at the first end, wherein the bottom is a closed container bottom, wherein the container further comprises an annular region;
• heating only the annular region of the glass container to a treatment temperature between 700 and 1000° C., wherein the heating is done from inside the glass tube;
• maintaining the treatment temperature for a period of time;
• and
• cooling the glass container to room temperature after the period of time has elapsed;
• wherein the annular region has an end facing to the glass container bottom and an end facing away from the glass container bottom, the end facing to the glass container bottom has a distance LB from the inside of the glass container bottom along a container axis of 0 and 20 mm and the distance LA between the end facing to the bottom and the end facing away from the bottom is between 1 and 10 mm.

A method for thermally treating an annular region of an inner surface of a borosilicate glass container,

• wherein the glass container comprises a glass tube having a longitudinal axis, a first end of the glass tube, and a second end of the glass tube,
• the method comprising the steps of:
• forming a bottom of the glass container on the glass tube at the first end, wherein the bottom is a closed container bottom, wherein the container further comprises an annular region;
• heating only the annular region of the glass container to a treatment temperature between 700 and 1000° C., wherein the heating is done from outside the glass tube;
• maintaining the treatment temperature for a period of time;
• and
• cooling the glass container to room temperature after the period of time has elapsed;
• wherein the annular region has an end facing to the glass container bottom and an end facing away from the glass container bottom, the end facing to the glass container bottom has a distance LB from the inside of the glass container bottom along a container axis of 0 and 20 mm and the distance LA between the end facing to the bottom and the end facing away from the bottom is between 1 and 10 mm.