If you haven't seen the recently published paper - Silicone Opacifiers for Spandrel Glass Applications: Risk Mitigation in Thermal Stressesyou should go see it now. The gist; the industry has known for a long time that ceramic enamel weakens glass. Up to a 40% weakening of heat-strengthened glass, depending on which study you grab a number from. Safely, 20% to 50% is the given range. EU standards for manufacturing safety glass take this into account, North American standards do not. Here are some visual examples of how silicone coatings, such as OPACI-COAT will reduce your risk in breakage from thermal stresses and offer fallout protection all in one.

Before you watch, the bottom-line, if glass isn't weakened, it withstands thermal stresses just fine. 

Are you willing to take the risk in your design?