When, if ever, did Negritude end as an active literary movement?

Negritude's founding is well documented to 1935, but sources describe its major publications and influence continuing through the 1940s and beyond without converging on a year the movement itself can be said to have closed. Later Francophone African and Caribbean writers, including some of Negritude's own students, criticized and moved past its premises gradually rather than at one identifiable moment, and Negritude's own founders remained active figures, Senghor as Senegal's president until 1980, long after any such close would fall.