I only had to stain the inside parts of our windows, and I used a combination stain/sealant from Minwax. It says drying time is six hours, but I remember it being dry to the touch within an hour or so.
As far as I know it's good for outdoor use too.
In ten years, it hasn't faded at all. The glass is treated to prevent UV fade, so I'm not sure how much gets through, but the windows get direct sunlight most of the day.