Pressure strength tests of windows in tempered glass

As the fabrication of large propane bubble chambers requires the performance of strength tests for the different constituting materials, this note reports strength tests of glass windows for such chambers. The author reports pressure strength tests performed on rectangular windows made of tempered glass operated at a constant temperature of 60 C, with every three seconds, an expansion which divides pressure by a factor of about 3,5, followed by a re-compression which lasts about 30 ms. Two type of windows have been tested: windows made of a 30.5 mm thick ordinary tempered glass, and windows made of a 50 mm thick borosilicate glass which has been polished, tempered and polished again after temper