Board Thread:Questions and Answers/@comment-26520349-20150630163324/@comment-1038387-20150630192019

There's no difference in universe between Silver and Bronze Age. It's just a change in tone somewhere in the seventies.

Golden Age is trickier, as the distinction was only made retroactively, and several characters have Silver Age histories that explicitly mention Golden Age adventures.

Anyway: for Superman and Batman, their first appearance Silver Age is (1952), IIRC. Wonder Woman is (1958). Aquaman is (1956). Green Arrow is a bit wishy-washy, I think retroactively it's (1959) or earlier.