I think the trick might be outer pane of glass, inner pane of non-glass. Glass would cut UV and handle the elements. Wood would be safer and insulate better.
You'd want the inner pane to be actual glass, too, so you can clean it with water or handle humidity. But at that point, the gap in a double-paned glass will insulate better.
I wonder if you could sandwich this in to one piece, like automotive glass -- glass/wood/glass?