polycarbonate skylight hazing

Why would a polycarbonate skylight haze to the point it looks like frosted glass?
Background: North Florida (Gainesville). About ten years, my mom replaced the glazing on the large (about 2.5x5') skylight in her kitchen with polycarbonate, partly on my recommendation. This was done by getting the piece of polycarbonate cut and fitted into the existing skylight frame, which dates from when the house was built in 1956, not by installing a new skylight. My mom died last year, and my sister is now living in the house.
Today we noticed that the skylight is severely hazed, to the point that it looks like frosted glass. Some of this could have happened gradually, but to the best of our memory it's mostly recent. Here's a photo looking up through the skylight
http://paleo.org/private/skylight-1.jpg
That's tree branches to the right and blue sky and clouds to the left. When it was glass, these were clearly visible, as through a window. Same when the polycarbonate was new.
The top of the skylight feels rough, and looks rough under slight magnification:
http://paleo.org/private/skylight-2.jpg
It's never been cleaned with anything harsh (just glass cleaner), unless someone has been sneaking onto the property and cleaning things without the knowledge of the resident. The tree branch overhead is live oak; currently no other kind of tree hangs over the house.
We tried a couple of forms of gentle cleaning, and nothing helped. It even continues to look just as hazed with water on it.
While it's true that there are advantages to diffuse light, in this case the views are good enough that we'd rather it be clear!
Any ideas why this has happened? Or what we could do to prevent it, if we replace the polycarbonate?
Edward
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Edward Reid wrote:

Yes, the ammonia in your glass cleaner reacted with the polycarbonate.
Now go get the appropriate novus polishing kit, and try to polish it back to clear, or start over with a new sheet and don't put ammonia on it this time.
Jon
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On 11/26/2010 8:52 PM, Edward Reid wrote:

If you installed the polycarbonate for safety and security reasons, you could replace it with a new laminate. The glass suppliers have a glass over poly that has the same strength as poly alone but it is scratch and chemical resistant because of the outer glass layer. It's not what would necessarily be called bullet proof but I believe there is a type that is hurricane proof. If wanted to be really cool, you can get the electrically controlled transparency glass. If you can't polish it out, it wouldn't hurt to talk to your local glass supplier to see what they have. You may be able to get some of the newer scratch and UV resistant polycarbonate from a plastics or glass supplier.
TDD
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On Fri, 26 Nov 2010 19:24:04 -0800, "Jon Danniken"

No ammonia has ever touched it. Phew. Nasty stuff.

hmm ... sounds like a plan ...
http://novuspolish.net /
thanks.
On Fri, 26 Nov 2010 19:26:18 -0800, Smitty Two

OK, thanks. I had thought of polycarbonate as totally resistant to sunlight, but obviously that was simplistic thinking. Basically resistant but with caveats ...
On Fri, 26 Nov 2010 22:27:46 -0600, The Daring Dufas

Not security in the sense of break-ins ... there are much easier ways to break in to this house. Safety mainly -- protection from broken glass, protection from whatever flying/falling object broke the glass, protecting the house from the elements when it breaks.

Interesting.
In a separate skylight investigation recently, I ran across some that are approved for south Florida -- IOW as hurricane-proof as can be. I also saw some that are glass, but use the kind of glass used in car windshields -- I forget what it's called but when it breaks, it breaks into innocuous granules instead of sharp shards. The glass is supposed to be extremely strong, but of course does not match polycarbonate.

Cool indeed. I found some. Seems there are three technologies. One costs about $90/sqft. Another costs about $125/sqft. With about 12 sq ft in this skylight, those aren't going to happen -- the shade mounted under the skylight has worked for over 50 years and still works. The third is predicted to cost only about $15/sqft, but I gather it isn't available yet. At that price, the shade might get replaced. And apparently some of these technologies can block up to 95% of the light while still admitting 80% or more when "open", which actually sounds better than the shade. "Smart glass" and "electrochromic windows" seem to be good search terms.
http://en.wikipedia.org/wiki/Smart_glass
says "The new Boeing 787 Dreamliner features electrochromic windows which replace the pull down window shades".

Lots of good ideas to pursue. Thanks!
Edward
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On 11/27/2010 12:41 PM, Edward Reid wrote:

The stuff that breaks into small chunks is "tempered safety glass" like the side windows on a car. A windshield is "laminated safety glass" meant to prevent you flying through the windshield during an accident. In commercial buildings, the doors and windows around entrances are required to have safety glass of either type installed. I've installed a lot of glass in commercial and institutional buildings. The laminated is better for security because it holds together making it more difficult for someone breaking in. You could install regular laminated safety glass in either standard or what I've installed before called Solarex which blocks UV. The standard laminated safety glass is not that expensive and will hold together if broken. It will also be chemical and scratch resistant. Talk to your local glass supplier, most of those I've met would be glad to help you out with a small order.
TDD
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wrote:

car headlights do this too, you mave be able to polish it out with buffing compound and electric drill. if you dont mind the work.
start at a auto parts store and try a small area before puutting too much effort in it
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On 11/27/2010 4:14 PM, snipped-for-privacy@aol.com wrote:

On my girlfreinds headlights (uh on her cars headlights) I first tried novus plastic polishing compound but it wasn't abrasive enough. Then I used auto paint rubbing compound, followed by polishing compound. Worked great but the kit is supposed to have a last coat that helps protect the plastic from future yellowing. I was tempted to spray come clear coat on them but didn't.
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