Just because "Glass" is input in the edit properties box in Revit doesn't mean that the box is actually linked to where you think it should be inside the family.
Where did you get the families?
I have a completely different workflow that I have described before but I use the great built in filtering to spit my Revit exports into a bunch of separate files (windows & doors, walls, etc) to have easy to create layers in max. Alternatively you can import it as a single object and then use material IDs to split it but if the materials aren't assigned correctly in Revit then you are screwed from the start.