I would look into 2 specific windows. Anderson 400 with its Fibrex material and Integrity by Marvin with its Ultrex material. Both materials are a form of extruded fiberglass with a special color finish. We have used both these windows and their performance is flawless. Make sure that you get all your hardware upgraded to stainless steel. Either of these windows should work very nicely for your project.

According to Andersen, Fibrex is a wood and vinyl composite, not fiberglass.