Yes, it can be done, and I have done this in my app. Take a look here: https://github.com/vinumeris/lighthouse/blob/master/client/src/main/java/lighthouse/Main.java#L474
I do it by taking a snapshot, then blurring that, then cross-fading, then replacing it with a live blur effect once done. I found this gave better frame rates than the simpler way of just animating the blur property of a blur effect, with very little visual degradation. Be aware that this won't work well on software pipelines, so I use some internal API to detect that and use a lighter weight effect instead. You can download a binary of the app from https://www.vinumeris.com/lighthouse if you want to see the effect in action (press one of the buttons at the top to trigger it).
