40 ILCS 5/9-149
A widow's annuity shall terminate when she remarries if the marriage takes place before the date 60 days after the effective date of this amendatory Act of the 91st General Assembly. If a widow remarries 60 or more days after the effective date of this amendatory Act of the 91st General Assembly, the widow's annuity shall continue without interruption.
When a widow dies, if she has not received, in the form of an annuity, an amount equal to the total sums accumulated and credited from the employee's contributions and applied for the widow's annuity, the difference between such accumulated annuity credits and the amount received by her in annuity payments shall be refunded to her; provided that if a reversionary annuity is payable to her or to any other person designated by the employee, this amount shall not be refunded, but the reversionary annuity shall be payable.
40 ILCS 5/9-149