Per IRS Publication 575 Pension and Annuity Income contains information in the Rollovers section (starting on page 28) regarding rolling over a distribution from a qualified retirement plan that is received under a Qualified Domestic Relations Order (QDRO). That specific information is contained on page 30:
Qualified domestic relations order (QDRO). You may be able to roll over tax free all or part of a distribution from a qualified retirement plan that you receive under a QDRO. (See Qualified domestic relations order (QDRO) under General Information, earlier.) If you receive the distribution as an employee's spouse or former spouse (not as a nonspousal beneficiary), the rollover rules apply to you as if you were the employee.
The same publication contains a definition for a QDRO on page 4:
Qualified domestic relations order (QDRO). A QDRO is a judgment, decree, or order relating to payment of child support, alimony, or marital property rights to a spouse, former spouse, child, or other dependent of a participant in a retirement plan. The QDRO must contain certain specific information, such as the name and last known mailing address of the participant and each alternate payee, and the amount or percentage of the participant's benefits to be paid to each alternate payee. A QDRO may not award an amount or form of benefit that isn't available under the plan.
A spouse or former spouse who receives part of the benefits from a retirement plan under a QDRO reports the payments received as if he or she were a plan participant. The spouse or former spouse is allocated a share of the participant's cost (investment in the contract) equal to the cost times a fraction. The numerator of the fraction is the present value of the benefits payable to the spouse or former spouse. The denominator is the present value of all benefits payable to the participant.
A distribution that is paid to a child or other dependent under a QDRO is taxed to the plan participant..