Heating part baked baguettes in lid-covered pyrex
I would expect the cooking time to increase significantly, and the texture to be very different (probably not very baguette-like. To mitigate this, you could preheat the pyrex container (put it in the cold oven, turn the oven on, and leave a few minutes after the oven claims to have heated up). I would also look for a way to ventilate the lid, like a wooden spoon sticking out.