I have a few questions about this but for now ill keep it simple....
when bending acrylic does it stretch or to put it another way grow?
example if you are working with a piece 2"X40" 3/8 thick and you put a 45deg bend in the 40" length will it grow longer?
i am pretty sure it stretches and thins out at the outside of the bend.... the inside of the bend should stay the same.. so essentially it should not grow longer....
Seeing as you're pulling out the outside of the acrylic and pulling it to make the 90 degree angle, yeah I would say it stretches and gets a tiny bit thinner. Couldn't say for sure though.