I have installed lexan
windows in hotrods and my camper. Downside of this material has been scratches.
Was at the track and this came up in the pit discussion. One of the guys was a hurricane film installer and said there was a product for plastic
windows. He offered to show me how to apply it at his shop. Did my windshield in a 6 mil clear. Can't tell it is on and on a scrap he had me practice on did the screw driver scratch test which it passed. It comes in a silver
solar shield also. Stuff is not inexpensive , but gin clear and no more scratches from road debrease. Similar to 3Ms hurricane film but designed to go on plastics which many films will bubble up on. Worth a Google if you are thinking about going with a replacement plastic window.