Could I suggest editing your post after visiting this guide FAQ: Tips for writing R-related questions?
It's not clear to me what you're trying to do, and what you've tried so far. I could try to help, but I'd be taking a wild guess as to what kind of plot of the "evolution of a correlation over time" means. This guide helps you improve your post such that others are more likely to be able to help.
For example, I'd love to see a reproducible example of what you've tried to do so far, (FAQ: What's a reproducible example (`reprex`) and how do I do one?).
That being said, you can plot a metric, like correlation, over time with ggplot. Here's a couple of examples,