No. What blocks UV is pigment. The clearer the finish the less
pigment. The less pigment, the less block.

Glass doesn't break down in sunlight, so pigment doesn't have to be a
requirement for to stand up to UV exposure. There must be some kind of
clear
finish that can be applied that won't break down when exposed to the
elements.

Glass isn't an air dried coating. You're attempting to compare apples
to oranges.

No, I'm simply stating that not everthing will break down when exposed to
UV. With enough money I'm sure someone could come up with a 20year clear
coating.

Of course, then you'd have to wonder who could afford it.