[en] Single-pass flow-through experiments were conducted with aluminoborosilicate waste glasses to evaluate how changes in solution composition affect the dissolution rate (r) at 40 C and pH(23 C) = 9.0. The three prototypic low-activity waste (LAW) glasses; LAWE-1A, -95A, and -290A, used in these experiments span a wide range covering the expected processing composition of candidate immobilized low-activity waste (ILAW) glasses. Results suggest incongruent release of Al, B, Na, and Si at low flow-rate (q) to sample surface area (S) [log10 (q/S) < -8.9 (m/s)] whereas congruent release was observed at high q/S [log10 (q/S) > -7.9 (m/s)]. Forward dissolution rates, based on boron release, are the same irrespective of glass composition, evident by the dissolution rates being within the experimental error of one another [r1A = 0.0301 ± 0.0153 g/(m2 d), r95A = 0.0248 ± 0.0125 g/(m2 d), and r290A = 0.0389 ± 0.0197 g/(m2 d)]. Finally these results support the use of a chemical affinity based rate law to describe glass dissolution as a function of solution composition