Ones that I'll bet are more than just very expensive.
But apparently actually in production.
Aerogel and polycarbonate combined to make a translucent roof panel.
On another list there's been some discussion of aerogels as insulating foam--up to R-60/inch, depending, of course.
First link's a story, second's the manufacturer.
http://renewableenergyaccess.com/rea/news/productstory?id=40121
http://cptsystems.com/
do you know how to make home made sun tubes? if so please email me at
kimcase9@hotmail.com thanks
or anyone reading this too thanks
Do you have a special area needing light or a special application for it Kimmer?
Here is some more information on plastic roofing products that might be of interest.
Lexan is a brand name for a nearly clear, UV resistant polycarbonate product that can be used for porch roof panels and other applications. There seems to be several new products coming out based on this material.
Here is a link to standard, single-wall corrugated roofing panels "Greca Corrugated" (http://www.advancegreenhouses.com/greenhouse_films.htm#Corrugated_Polycarbonate_Sheets).
(http://www.advancegreenhouses.com/corrugate.jpg)
Here is another similar material designed to fit the corrugated roofing panels used in metal buidings (https://www.sundancesupply.com/index2.html).
(https://i56.photobucket.com/albums/g166/jraabe/panel.jpg)
Here are some uses for the generic term Polycarbonate Roofing Panels (http://www.polycarbonatesheets.co.uk/home.html?mid=ghs).
A good overview of the various types of clear and translucent roofing products - this from the world of Greenhouses (http://h2othouse.com/html/greenhouse_glazing.html).
And finally, another high-tech insulated clear roofing product that could be used for interior skylights:
"LEXAN ZigZag (http://www.buildingtalk.com/news/gea/gea103.html) offers light transmission even higher than single glass, combined with insulation values the same as double glazing. Key to this new higher level of light transmission performance is the special shape of the twin-wall panel that reflects light back into the greenhouse thereby compensating for any light loss due to the panel's double wall."