  We have conducted experiments on the effect of polymer solutions on the
formation and propagation of vortex rings. We study this effect in aqueous
solution of hydrolyzed polyacrylamide (PAMH) at different concentrations.
Addition of PAMH imparts shear-rate dependent viscosity and elasticity to the
solvent. With increasing concentration of PAMH both the zero-shear-rate
viscosity ($\eta_0$) and the infinite-shear-rate viscosity ($\eta_{\infty}$)
increase. The relaxation time also increases with the increase in
concentration. We generate vortex rings using a piston-cylinder mechanism in a
glass tank and measure vortex ring properties such as ring position, ring
circulation, enstrophy, kinetic energy and peak vorticity using particle image
velocimetry (PIV). Experiments are conducted by (1) matching impulse, and (2)
matching Reynolds number. We show that, at constant impulse, vortex ring
properties in PAMH solution deviate from that in Newtonian water. As the
concentration of the PAMH solution increases, so too does the deviation from
water. We further perform experiments in water by matching the limiting
Reynolds numbers of the PAMH solution corresponding to both $\eta_0$ and
$\eta_{\infty}$. We find that while the circulation of PAMH solutions lies
between the circulation curves of the two extreme Reynolds number matched water
experiments for an extended period of time, the enstrophy and peak vorticity do
not. We attribute this behavior to the modification of vorticity distribution
within the core of vortex rings in PAMH solutions. We also study the effect of
polymer solutions on the formation number. We find that the formation number
remains the same even in polymer solutions. We also demonstrate, using planar
laser induced fluorescence (PLIF), the phenomenon of ring reversal.
