Abstract: The invention relates to a process for the heat-soak treatment of tempered glass panels. After tempering, the glass is heated or cooling of the glass is stopped for maintaining the temperature for the duration of e.g. a good minute within the range of 340-370.degree. C., such that the glasses, which break spontaneously in time as a result of NiS-stones, can be broken already in a so-called heat-soak treatment. During the heating sequence or the cooling stop sequence and during the subsequent cooling sequence, the glass panel is carried in a horizontal plane, e.g. back and forth on rollers in an oscillating fashion. The process is a continuous-action process and the apparatus for implementing the same can be hooked up with a tempering machine for an on-line operation.