A roof window pane shattered weeks after installation. What happened?

Method 1: It is possible that there was a film malfunction, or the wrong film was installed. If the window in question has film on it that absorbs more heat than the glass can handle, then it can shatter eventually.  But if that were the case, then all panes would be broken, not just one. If the glass is tempered, the film is most likely not the problem as tempered glass can take almost any amount of heat.   Method 2: Another possible cause of the shattered glass is something called nickel sulfide infusion which happens to toughened glass. Nickel sulfide infusion (NiS) is a known defect in toughened glass where nickel contaminates the glass melt and reacts with sulfur. NiS can be somewhat determined by the pattern of which the pane breaks into, but the only sure way to identify it is to collect the broken remains and have your supplier analyze it for you. If it’s a small fix on your job, eating the cost of a new window is usually a cheaper and faster route to satisfying the client.