Genelec 8020

well, glass is thin.
 
unless it is a really nice performance window, thicker glass, gas in the void, double pane...
 
are you worried about sound going out....... or coming in?
 
the glass will cause some issues with your high end, for sure...
but it is very easy...
to create a panel, with some kind of insulation or sound treatment, 
to temporarily fit into the window box while you mix.
 

The window shouldn't be too big a problem. Just try to center the window between the speakers if you can, and pull them as far away from the window and back wall as possible. Your biggest problem will simply be that the room is small. Are you willing or able to add acoustical treatments to the room?

Start with a visit to Ethan Winer's Realtraps site. There is a lot of excellent information there on acoustic treatments you can do yourself. You're going to need lots of absorption in that room, especially in the corners.

Thanks guys :)