Glass scratches

If you are referring to the windshield, no there is no coating on the glass, certainly nothing plastic. There is a molecular-scale layer of Potassium or Lead used in the tempering process, but that's different.

What is most likely happening is that dirt, dust and debris trapped on your scraper or already deposited on your windshield, before the ice and the snow, is what's doing the scratching. Keeping your windshield clean and a proper application of Aquapel or similar would help mitigate this.

You can try buffing it out with Ceriglass, but it requires a LOT of down pressure and elbow grease to be effective, and if the scratch is deep enough to catch your fingernail, then it won't do you any good. And you have to do the entire windshield, otherwise you end up with spotty hydophobism.

There does exist a plastic coating, similar to clearbra, that very high-end cars put on their windshields, which prevents most scratches and pits from sand and road debris. I can't think of the name at the moment, but it's quite expense.

The Prius C windshield is purposely made very thin, for weight saving and therefore gas mileage reasons, and it breaks very easily, as I found out when a puny falling pine cone totally bashed mine in a couple of years ago.

 

For you or others interested, here's a Cliff's Notes version of how to properly clean the outside of a windshield:

1. Wash the windshield with sponge or wash mitt. Make sure all tree sap, road debris and gunk is gone. Tree sap can be removed by rubbing alcohol;
2. Use a pad of 0000 steel wool and undiluted liquid car wash (or Dawn dishwashing liquid). Put the liquid on the steel wool and go over the entire windshield. Use down force here. Don't worry - you won't scratch it.
3. Rinse off with distilled water.
4. Dry off with a leaf blower or a sheet of newspaper. Some folks like microfiber towels, but I prefer newspaper.
5. Apply Aquapel or your choice of water repellent.