I'm planning on doing a complete renovation of my
straight-from-the-1960's bathroom. One of the issues that I want to
fix is the old wooden window in the shower. Right now there's a
plastic curtain in front of the window that's there to prevent the wood
from getting wet and rotting.

I'd like to replace the old wood window with a vinyl window and finally
getting rid of the plastic curtain, as showering in between two plastic
curtains (the window curtain and the shower curtain) isn't my
preference.

1st question is whether it is an issue if the inside of a vinyl window
gets wet? Obviously windows are designed so that they can get rained
on from the outside. What about the inside of the window? Will this
be an issue, and/or do they design certain types windows specifically
for such settings? I'm trying to figure out whether an awning or
hopper window would be best for not collecting water on the inside
(i.e. I imagine a horizontal sliding window would collect water in the
"groves" at the bottom)

The entire bathwall would be tiled and I'd make sure that the window
sill would be sloped downwards towards the bath tub so that any water
can drip away. Concerning that material, I've read about one company
that uses Corian instead of wood for such a purpose. To me it does
seem to make sense instead of having a wood window sill/trim that can
rot over time. Does using Corian sound like a good idea or something
crazy?

I know that the simple solution would probably be simply to remove the
window completely and use glass blocks instead, but I'd prefer having a
functional window even if it means paying more. As long as it doesn't
cost WAY more.