There is a company in Texas who makes deer blind doors and windows. Reasonable cost. I like their doors a lot. Full piano hinge, RV style door handle, seals out wasps and bugs very well.
Can’t remember the company though.
Also, I have ordered RV windows off eBay for another build (I’ll post soon). They are ok, they don’t leave a lot of room to shoot and they are tinted, but good enough.
I have built good secure windows out of plywood and Poly or plexiglass. I’ll try to explain the best method here.
For example, Cut a piece of plywood that is 4” larger than the cutout in the blind (24x24 plywood for a 20x20 hole in the blind wall)
On that plywood, Cut out a 18x18 hole in the very center. I use a router to make a channel around the inside of this hole, recessed to silicone a piece of plexiglass in. (Install plexiglass last)
Now, mark a 21x21 square in the center. Plunge cut with a skill saw three sides of the square. Do not cut the 4th side yet.
Screw your hinges on to one of the 3 cuts. This keeps your reveal perfect around the entire window.L once the 4th side of the square is cut.
You wind up with a 24x24 outer frame, a 21x21 window frame and a 19x19 window.
The reveal around the hinged window is a perfect 1/8” and you can mount it to swing up, down or to either side. You can add strips of wood on the outside to completely seal off the 1/8” gap as well.
Hope that was clear!