Wrap in shrink wrap and caulk repeatedly until sweaty????

I had some success with using those dissicant packs that come in electronic packaging to keep them dry. Put them between the plastic and the glass window.

I used the shrink wrap and have taken large foam insulating sheets and made round windows with plastic wrap or plexi glass. Plastic wrap worked best. Light wieght and reuseable for years. Just seal with theclear insulating tape which is great stuff.

Using the foam panels with smaller clear plastic windows put an end to the sweaty large window that was near the bathroom door. I had previously used a plexi glass insert but the condensation on the glass part was awful.