Method for heating molten glass and glass article

A glass article, the glass article being designed at least in part in form of a glass tube element comprising at least one shell which encloses at least one lumen, wherein for at least one light transmission analysis of the glass article, a ratio of an average amplitude transmission factor and a specific amplitude transmission factor is greater than 1.00003, wherein for the light transmission analysis, an outer surface of the at least one shell is at least virtually divided into surface areas of equal shape and size, and an amplitude transmission factor of a light beam, which is emitted from a fixed light source towards a fixed detector along a beam path, is determined consecutively for every surface area in that the glass article and/or the surface area is positioned relative to the beam path such that the light beam propagates through a thickness of the at least one shell and crosses the respective surface area perpendicularly, wherein the amplitude transmission factors of all surface areas are arranged within a sorted list from small values to large values, wherein the specific amplitude transmission factor is the mean value of the first 1% of the amplitude transmission factors arranged in the sorted list, the smallest one being among the first 1% of the amplitude transmission factors, wherein the average amplitude transmission factor is the mean value of all amplitude transmission factors arranged in the sorted list;

• wherein the at least one shell has an overall average concentration of molybdenum, platinum, iridium, tungsten, rhodium, noble metals, alloys of one or more of these materials or oxides of one or more of these materials, respectively, of at least 0.1 ppm (m/m) but less than 50 ppm (m/m);
• wherein the amplitude transmission factor is the factor the amplitude of the light beam is attenuated between the light source and the detector;
• wherein the light beam has a wavelength of between 270 nm and 300 nm;
• wherein the light source comprises a laser;
• and
• wherein the outer surface of the at least one shell is divided in 10 or more equal surface areas.

A glass article, the glass article being designed at least in part in form of a glass tube element comprising at least one shell which encloses at least one lumen, wherein for at least one light transmission analysis of the glass article, a ratio of an average amplitude transmission factor and a specific amplitude transmission factor is greater than 1.00001, wherein for the light transmission analysis, an outer surface of the shell is at least virtually divided into surface areas of equal shape and size, and an amplitude transmission factor of a light beam, which is emitted from a fixed light source towards a fixed detector along a beam path, is determined consecutively for every surface area in that the glass article and/or the surface area is positioned relative to the beam path such that the light beam propagates through the thickness of the at least one shell and crosses the respective surface area perpendicularly, wherein the amplitude transmission factors of all surface areas are arranged within a sorted list from small values to large values, wherein the specific amplitude transmission factor is the mean value of the first 1% of the amplitude transmission factors arranged in the sorted list, the smallest one being among the first 1% of the amplitude transmission factors, wherein the average amplitude transmission factor is the mean value of all amplitude transmission factors arranged in the sorted list, wherein there is on less than 5% of an outer surface area of the at least one shell local striae of molybdenum, platinum, iridium, tungsten, rhodium, noble metals, alloys of one or more of these materials or oxides of one or more of these materials, respectively, when a volume of the at least one shell is projected radially outwards on the outer surface of the at least one shell;

• wherein the amplitude transmission factor is the factor the amplitude of the light beam is attenuated between the light source and the detector;
• wherein the light beam has a wavelength of between 270 nm and 300 nm;
• wherein the light source comprises a laser;
• and
• wherein the outer surface of the at least one shell is divided in 10 or more equal surface areas, wherein the at least one shell has an overall average concentration of molybdenum, platinum, iridium, tungsten, rhodium, noble metals, alloys of one or more of these materials or oxides of one or more of these materials, respectively, of at least 0.1 ppm (m/m) but less than 50 ppm (m/m).