My hall bath has a partially enclosed tub. I have researched an L-shaped shower curtain rod and know that they exist, however, I would like the longer part of the "L" to be curved to allow for more room in the tub when taking a shower. Can I curve the longer portion myself successfully and easily without harming the curtain rod?
It depends on how brittle/ductile the rod is. Its likely steel, which has a wide range of properties. There may be finish cracking issues. The wider the radius, the more likely the success.
I would experiment on a similar but simpler rod. The methods I suggested here would be the least expensive tooling.
Essentially, if you had some basic workshop tools you could, you could very easily curve the shower curtain yourself, but the problem is making the curve look professional.
If you are keen to experiment, I would fill the tube with fine sand, then close the ends with a stopper. Then you will need to look for somewhere to bend the rod, typically one would use a set of rollers with the desired bend profile, however in the DIY sense the best thing you will find is to look for a strong tree (specifically a split or v in the branches) whereby you can gain leverage for the bend. Then very gentle pressure all down the bend seam will begin to bend the bar.
The better thing to do here would be to take the curtain rod to a metal shop and have them try, in which case I would go for stainless steel or aluminium which will not flake.