According to this article - How Fast Should Your UI Animations Be? your start point is within a reasonable starting range.
200ms to 500ms is a good range to start with for interface animations.
You can also take into account the guide posted in the article:

Because, among other reasons, according to the Nielsen Norman Group (Response Times - 3 Important Limits):
100ms is perceived as instant, and 1 second is considered the upper limit of a user’s flow of thought.
This is UX we're talking about though, so take into consideration what kind of user is going to use what you're animating instead of just following a guide.
I don't expect you'll find a ton of information on this because it's the kind of thing that, just as you have done, can initially be intuited within a reasonable range of acceptability, and any issues that arise are easy to find with even the most basic user testing.