Pyrex doesn't have a maximum temperature limit in a kitchen environment if you are careful. Preheating the oven is the #1 way to prevent issues. If you put a piece of glassware in an electric oven without preheating it, you can create massive temperature deltas between top/bottom. I can get an iron skillet beyond 700F in my electric oven if I leave it in there while it's preheating for a set point of just 450F. If the heating element has direct line-of-sight to the cookware, you always need to be wary of radiative heating effects.