Objection 1. It would seem that our souls are contrite for sins even after this life. For the love of charity causes displeasure at sin. Now, after this life, charity remains in some, both as to its act and as to its habit, since "charity never falleth away." Therefore the displeasure at the sin committed, which is the essence of contrition, remains.
Objection 2. Further, we should grieve more for sin than for punishment. But the souls in purgatory grieve for their sensible punishment and for the delay of glory. Much more, therefore, do they grieve for the sins they committed.
Objection 3. Further, the pain of purgatory satisfies for sin. But satisfaction derives its efficacy from the power of contrition. Therefore contrition remains after this life.
On the contrary, contrition is a part of the sacrament of Penance. But the sacraments do not endure after this life. Neither, therefore, does contrition.
Further, contrition can be so great as to blot out both guilt and punishment. If therefore the souls in purgatory could have contrition, it would be possible for their debt of punishment to be remitted through the power of their contrition, so that they would be delivered from their sensible pain, which is false.
I answer that, Three things are to be observed in contrition: first, its genus, viz. sorrow; secondly, its form, for it is an act of virtue quickened by charity; thirdly, its efficacy, for it is a meritorious and sacramental act, and, to a certain extent, satisfactory. Accordingly, after this life, those souls which dwell in the heavenly country, cannot have contrition, because they are void of sorrow by reason of the fulness of their joy: those which are in hell, have no contrition, for although they have sorrow, they lack the grace which quickens sorrow; while those which are in purgatory have a sorrow for their sins, that is quickened by grace; yet it is not meritorious, for they are not in the state of meriting. In this life, however, all these three can be found.
Reply to Objection 1. Charity does not cause this sorrow, save in those who are capable of it; but the fulness of joy in the Blessed excludes all capability of sorrow from them: wherefore, though they have charity, they have no contrition.
Reply to Objection 2. The souls in purgatory grieve for their sins; but their sorrow is not contrition, because it lacks the efficacy of contrition.
Reply to Objection 3. The pain which the souls suffer in purgatory, cannot, properly speaking, be called satisfaction, because satisfaction demands a meritorious work; yet, in a broad sense, the payment of the punishment due may be called satisfaction.
Source: Summa Theologica (New Advent)