  Strongly quasipositive links are those links which can be seen as closures of
positive braids in terms of band generators. In this paper we give a necessary
condition for a link with braid index 3 to be strongly quasipositive, by
proving that in that case it has positive Conway polynomial (that is, all its
coefficients are non-negative). We also show that this result cannot be
extended to a higher number of strands, as we provide a strongly quasipositive
braid whose closure has non-positive Conway polynomial.
