Window in shower stall

[urbantumbleweed]

I'm planning on renovating our bathroom within the year. We have one window in the bathroom, which is in the tub. It has a sill and water collects there no matter what. We are considering putting in a glass block window, but I read someone say on Apartment Therapy they did that and it's constantly moldy no matter how much they scrub.

Has anyone had success with shower windows? Suggestions on what to do? I'm not having much like googling people's actual experiences.

* I'd prefer to keep the window because it's the only one in the bathroom.