Notepad would create a temp file when it goes into Hibernation. But recovering files from hibernation is tricky.
You might be lucky to find a tmp file with the name since you have a workspace on your desktop that was in use. But again tricky.
Notepad isnt the best when it comes to auto saving or creating temp files.
If you are in dire need of that information i would suggest a look into notepad++ which has those options.