I have your fix for the water leaking and it doesn't require bullet proof glass. We have this same problem on PC because water physics are still in early stages and kind of garbage at the moment.
If you want a glass pool or something similar the only way to keep water from leaking out is to use 2 blocks. Now this can be 2 full blocks or a full block and a plate, or even 2 plates rotated to sit against each other.
So for the bottom of a roof glass pool, you can use glass plates rotated to the bottom of the block rotation and underneath you can put another glass plate rotated to the top position to sit flush against the one above it. This will keep your water sealed in. You can do this for the sides as well.
I have tested and built this many times on PC and console so I can guarantee you it works. I have also built underwater bases out of concrete and glass and it worked perfectly.
If you have any questions, let me know.