Interesting question. Actually, there are many types of glass, along with various coatings, as well as plastics that look like glass. From experience, I can tell you that they do not all behave the same way. For example, I find that shooting through an airplane window poses few problems, but shooting through glass at an airport terminal often causes a lot of problems (blurring, reflections, etc.)
I believe the use of a polarizing filter will help to minimize reflections by excluding off-axis light waves.