Not a Voyager episode, I think you are thinking about an episode of Enterprise featuring a sect of Vulcans called "V'tosh Ka'tur" or "Vulcans without logic"
It was the Enterprise episode "Fusion" (Episode 17 of Season 1). They were mentioned again in the episode "Stigma" (Episode 14 of Season2) where T'pol learns she has contracted Pa'Nar Syndrome.
Star Trek: Voyager, Caretaker Part 1 (the pilot episode), in a scene set in the Mess Hall (the first of its kind), at about the sixteen minute mark, features a couple of female Starfleet officers conversing. The more prominent of the two is Vulcan, and she is smiling or laughing while talking.