What causes this defect in glass?

Robinson-Solutions Professional Window Cleaning: Newtons Rings - Window Cleaners Glossary I’m always curious about Newton rings showing up in large ig duo paned glass. Is it because the ig windows are made at a different elevation than where they’re installed at? And they suck in? Concave in? I’ve never seen windows bow out? I’ve noticed some manufacturers have breather tubes. Is that to deal with changes in elevation? Hmm

[MENTION=410]wateron[/MENTION]- curvature in the glass can be due to various reasons. This article has a good explanation of many of those reasons, which can also lead to window implosion: Exploding Double Glazing, Imploded Double Glazed Sealed Units, cracked, damaged, fault

I beleive that the tempeture is he culprit. Notice that failed windows do not have this curvature problem. I have actually seen windows in a house that were 5’ tall and 3’ wide that were bowing out top to bottom because the headers over the windows were not done correctly. The scary part is that they (3 of them) were bowing towards the familys kitchen table. An accident waiting to happen.

I have seen windows strait from the manufacturer that where bowed so badly that we could not even get them in the frame. The panes went in the dumpster and new ones where made. I have also seen units touch in the center from bowing causing a form of the colors mentioned.