This study examined linear viscoelasticity (LVE) of semidilute non-entangled poly(vinyl alcohol) (PVA) and borax aqueous solutions: one borax molecule dissociates into two B(OH)₃ molecules and two B(OH)₄⁻ ions, and the latter can crosslink the PVA chains. Gelation was observed with increasing concentration of borax in the solutions. Analysis of LVE with the reversible gelation model reveals that although the number density of crosslinking ions increases with increasing concentration of borax, the fraction of the crosslinking ions decreases, which is attributed to the intensified electrostatic repulsion when more sites of the PVA chains are occupied by the ionic crosslinkers.