Abstract: This invention relates to first and second plate glass templates each having an outer smooth major surface and an inner rough major surface, only each of the major outer smooth surfaces being peripherally bounded by a chamfer formed at the cut edge. In this invention, the first and second templates are joined together with the rough surfaces in facing retention. The first and second plate glass templates may be used in forming a window.

Abstract: A determination of the temper quality of a tempered glass sheet is made which includes determining the percentages of the thickness of a tempered glass sheet which are in compression as well as the sheet's tensile membrane stress. The process uses a CO.sub.2 laser beam, either on a painted or unpainted glass sheet, to shatter the glass sheet and then comparing the number of pulses required for the glass sheet to shatter to a correspondence, e.g., a graph, of tensile membrane stress v. compression layer thickness as a % of the total thickness of the glass sheet.