I used 1/4" tempered glass for sliding glass doors on my salvator enclosure. I have no complaints, other than the substrate getting in the track making them difficult to slide sometimes. I'd use a different track if I had it to do over, but all I could find locally was the inexpensive plastic track. I still may change it at a later date. The glass has been tail whacked pretty good several times and is still holding up strong. The other thing I did was get a sliding glass cabinet door lock, so my enclosure is secured with a keyed lock at all times. Visitors and children cannot gain access easily. You'd be surprised how stupid people can be sometimes, lol.
I would not consider sliding plexiglas for a salvator enclosure. If it's not firmly anchored a strong monitor can push it out of a track because it flexes. Strangely enough the tempered glass, even though it took 3 days to get, ended up being cheaper for me here than untempered would have been. I was jonesing to get the cage done and considered untempered glass, until I got the quote, LOL. If you do decide to go with glass, make sure to order the edges polished, it only costs a few bucks more.
Good luck!