Okla. Stat. tit. 84, § 114

A. If, after making a will, the testator is divorced, all provisions in such will in favor of the testator's spouse so divorced are thereby revoked. Annulment of the testator's marriage shall have the same effect as a divorce. In the event of either divorce or annulment, the testator's former spouse shall be treated for all purposes under the will as having predeceased the testator. Provided, however, this section shall not apply if the decree of divorce or of annulment is vacated or if the testator remarries his former spouse, or following said divorce or annulment, executes a new will or codicil which is not revoked or held invalid. B. This section shall apply to any will of a decedent dying on or after November 1, 1987.