What happens if I use fins of white opaque but translucent glass as fins angled to exclude summer sun?

Arrayed above clear glass overhead glazing, I can arrange them to intercept direct penetration thro the glazing below into the interior by summer (equinox to June solstice) sun; but to allow winter (Dec solstice to equinox) sun to penetrate.

The fins would be made of Pilks self-cleaning glass, so would themselves shine brightly while illuminated by sun, even while blocking the sun's rays from going further. That way, I hope that they'd strongly illuminate the interior, like a bright overcast sky, the thro clear glass overhead glazing into the interior.

The question is, do the white opaque but translucent fins intercept solar rays by a) reflecting them, or by b) absorbing their heat and re-radiating?
If a), then they would simply bounce the rays thro the glazing into the interior.
if b), they would be somewhat cooled by convection before re-radiating about half (from one of their two surfaces) thro the glazing into the interior.

If shining brightly, to illuminate the interior, is this pro rata with the infra red also being radiated into the interior.

I'd really appreciate some illumination (!) on the physics of this - absorbency, reflectivity etc incl whether either of these can be maximised for the visible spectrum, minimsed for infra red.

Thanks a lot Will.

As I hoped, and yes of course as selective coatings show, absorbtion vs reflection can be manipulated depending on wavelength. Haven't quite thought it through yet but there's scope.

Posted By: WillInAberdeenin Dec the sun would only come through at noon, not for the rest of the day. How about reducing the angle?

My diagram is a section drawn in N-S plane. Yes, before and after noon, sun elevation is lower but it's also coming not from S but from SW/SE (more or less), from which the 20o tilt of the fins looks lower: tan-1(tan20.cos45) = 14.4o = sun elevation (from SW/SE) about Nov 4. From E/W the tilt looks like 0o. The 20o tilt of the fins is roughly same as an average of the winter sunpath planes (could be further optimised). So winter sun (on given date) will penetrate to similar degree right from E to S round to W.

Cobwebs - the fins are mounted well clear above the patent glazing so hopefully all would wash down.

I hope the fins will get hot - so that natural covection will cool them, reducing their re-radiation compared to unobstructed solar radiation.

Clouds - the objective is to maximise (the mainly light, less infra red) scattered radiation penetrating between plus re-radiating from the glass fins on cloudy days, while minimising (the more infra red) directional radiation intercepted by plus re-radiating from the glass fins on summer sunny days.

Valuable - thanks - incl to stimulate my responses. Any more insights?

External blinds/shutters would be easier - big Velux(es) so equiped is an option, but not so elegant or illuminating (to the inboard room) as full triangular (between roof valley slopes) patent glazing. I'd hope that such blinds would automatically deploy/retract like a yoyo as direct sun comes and goes!

As Will says, I'd worry about leaves and other detritus collecting, leading to plant growth, unless cleaned somehow.

It sounds like a scheme that needs a full-size model building first, to check out all the details including the basic operation and any other aspects.

https://www.yet2.com/active-projects/offering-window-film-reflects-high-angle-solar-heat-rays-back-to-the-sky-rather-than-warming-nearby-ground/