That's what we are working to substantiate. Stay tuned for more statistical data if that's your kind of thing. 
[UPDATE: The statistical data is in! Click link to view/download the white paper - ]

What we do know is ceramic enamel (frit) weakens heat-strengthened and tempered glass. It has been demonstrated and proven by many sources, including the frit manufactures themselves. We also know that the heat gain in a spandrel cavity can get quite high. Couple the two together and thermal breakage occurs, and it’s happening more and more. 

Want a glass coating that doesn't weaken your glass, and can offer fallout protection when applied at 13 mil wet film thickness? Maybe you also want virtually unlimited color choices and have a desire to use eco-conscious, water-based (not solvent) products with no heavy metals introduced (in any color), therefore providing a safe work environment for production employees and end-users alike? We agree, this isn’t too much to ask of your spandrel glass coating product.

It sounds like OPACI-COAT-300® may be an excellent fit for your needs. 
Download the updated, performance-enhanced spandrel specification here.
Get your hand on some free samples too! Click here.

I'll leave you with this great video – 13 mil wet film applied OPACI-COAT-300®, a 1.18# steel ball dropped from 11’6” height. This is an actual ASTM test standard for breakage of glass.
Note: Uncoated clear tempered glass breaks around a 4’ high ball drop.