yes, there are. a google search for 'Fix RV Fogged Windows' should turn up several.
we had a bunch de-fogged at Suncoast Designers in Hudson, FL several years ago and can recommend them without reservation. two others that immediately come to mind are the RV Fog Doctor in Searcy, Arkansas and Dave Root RV Glass in Bend, OR.
good luck.
Rich
Ham Radio, Sport Pilot, Retired 9-1-1 Call Center Administrator
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2016 Itasca Suncruiser 38Q
'46 Willys CJ2A
'23 Jeep Wrangler JL
'10 Jeep Liberty KK
& MaggieThe Wonder Beagle