I would devise some kind of panels that keep the hive covered, and in darkness, except when you slip them off to look at them. Unless the hive is in very deep shade I think having it exposed will also contribute to heat build-up. And by very deep shade I mean a place where it is unlikely to be good to have the hive in the first place. Indoor OBS are different because their entrance point is out in the sun, even if they are exposed to ambient light indoors.
I know that occasionally bees will build their combs completely out in the open if they have no choice about it, but in that case there is nothing trapping heat around them like a Lucite box would.
My bees readily propolize over even small peep holes that are covered with Lexan, unless I keep the the plastic covered with a solid material except when I'm peeking at them.
Agree with what Enj says:you'll be building a greenhouse. Heat buildup with any direct sunlight can happen very quickly. Also, less insulative in winter compared to wood.
As far as light in general, my OH gets morning sun from a window and room lights all day. They build out and have brood on the face like it was in the dark; no problem. I think they don't care as long as they are secure. Also, Bee Space is essential or they will burr comb it up.
One problem with keeping observation hives dark is that the bees will behave differently when suddenly exposed to light for observation.
I've built several o-hives, mostly standard Lang's with 4 double windows, but also one coffee table hive with a fly-out tube going out the wall (yes, 2 shut-off switches and a quick-connect scheme, roll the table outdoors for work). The bees adapt to diurnal light.
I have to adjust my previous comment about sunlight. My WindOH hive now gets direct light at sunrise for a little while from across the office coming in another window. It's a pretty bright office anyway because of all the big windows but now near the summer solstice the sun rises really far "north" in the east. They don't seem to like it. At first I thought it was failing but an inspection showed nice full frames and all the right stuff. I still love it and won't try to shade the opposite window (because I also love all the light in the office).
So plan for this if it will get true, direct light. Otherwise, my comments about light remain. My other OH on our sunporch (bright, indirect light) is full right on the front.