40 ILCS 5/13-305
A surviving spouse who was married to an employee on the date of the employee's death while in service, or was married to an employee on the date of withdrawal from service and remained married to that employee until the employee's death, shall be entitled to a surviving spouse's annuity payable for life. However, the annuity shall not be payable to the surviving spouse of (1) an employee who withdraws from service before attaining the minimum retirement age unless the deceased employee had at least 10 years of service, or at least 5 years of service if the employee was eligible for an annuity upon attainment of age 62 pursuant to Section 13-301(b) or had been receiving a retirement annuity pursuant to Section 13-301(d), or (2) an employee not described in item (1) who first enters service on or after the effective date of this amendatory Act of 1997 and who has been employed as an employee for (i) less than 36 months from the date of the employee's original entry into service or (ii) less than 12 months from the employee's date of latest re-entry into service; except as otherwise provided in Section 13-306(a) for an employee whose death arises out of or in the course of the employee's service to the employer.
Notwithstanding any other provision of this Section and notwithstanding the forfeiture of rights provisions under subsection (e) of Section 13-601, surviving spouse annuity eligibility or eligibility for alternative survivor's benefits, if applicable, shall be extended to the spouse or civil union partner of an annuitant who retired prior to June 1, 2011 and received a refund of surviving spouse annuity contributions as provided in subsection (b) of Section 13-601 if the annuitant (i) repaid the surviving spouse annuity contributions under subsection (b-5) of Section 13-601, (ii) could not enter into either a civil union or marriage recognized in the State of Illinois prior to that date, and (iii) became:
A dissolution of marriage after retirement shall not divest the employee's spouse of the entitlement to a surviving spouse's annuity upon the subsequent death of the employee, provided that the surviving spouse and the deceased employee had been married to each other for a period of not less than 10 continuous years on the date of retirement.
For purposes of Section 1-103.1, the changes made by this amendatory Act of the 100th General Assembly apply to persons not in service on or after the effective date of this amendatory Act of the 100th General Assembly.
40 ILCS 5/13-305