I remember on the cartoon show
Alvin and the Chipmunks had a character named
Brittany. The Chip-ettes (female counterparts to the Chipmunks) were
Brittany,
Jeannette, and
Eleanor. This show was on 1983-1990, so it may have been too late for the rise of the name. I remember that was the first time I'd ever heard the name, though!