I came up with a decent analogy for glass tanks just now...

Picture yourself inside your car during the winter. Your heat is on, and its warm inside the car. But your feet are still cold, and the glass windows are freezing cold to the touch.

An extreme example, but similar to what your BP could experience inside a glass tank that large.

Like adam said, be more worried about the temps inside a glass enclosure that large. If you wanted a snake for a vivarium, a ball python wasn't the right choice of animal to go with. Ball pythons love plastic.