Back when I was in shop class we had some projects out of Plexiglas, using colored and clear. We glued it together using acetone, to the best of my memory we wiped one side with acetone and let it sit for a few seconds and the clamped it together. We never turned the glued blanks, but we did drill and create flower looking stuff with a Foredom type tool.
I am sure Plexiglas would machine pretty good, but have never done it on a lathe. I think I remember a penturner using colored sheets of Plexiglas to fabricate a pen blank, which is one reason I believe it will machine okay on the lathe. I have milled Plexiglas on mill, it cut pretty good but it is MESSY as can be. To fast and it will glue itself to itself.
Marvin