I need to get some new risers. Most everything here .. 150 or so .. are 1" at the base and neck down for a 3/4" impact. Well, the newest load of pipe is set up for 3/4" risers. Got to wondering if PVC would work or if it is too flexible, absorbs too much of the impact so the sprinklers don't turn. Thoughts?

White PVC can not take much sun light.

True .. the biggest difference between white PVC and the grays type conduit is the fact that the conduit has not been pressure tested that has been treated for UV light the PVC has been pressure tested but not treated for UV light

In a lot of nut orchards here in Ca when they used to use "solid set" irrigation systems....basically permanent impact sprinklers they almost exclusively used schedule 40 WHITE pvc and those risers would last the life of the orchard...up to 30 years.... granted not really direct sun under the trees but I have ZERO issues with using schedule 40 white pvc above ground.