Pore structure plays a great role in determining the physical and mechanical properties of a gel. In this study, a polyvinyl alcohol (PVA) based hydrogel has been synthesized using glyoxal as crosslinker, and the influence of diethylene glycol (DEG) as a porogen in modifying its properties has been investigated. The resulting hydrogel possesses a unimodal distribution of nanopores, the content & sizes of which are controlled by using various dosages of porogen. The hydrogel has been characterized using FTIR spectroscopy which confirms the acetal linkage formation caused by the crosslinking reaction. The presence of DEG influences its rheological properties & decreases its glass transition temperature (T_g). Cyclical swelling–deswelling of the hydrogel samples leads to their improvement. DEG also assists in modifying the thermo-responsive nature of the crosslinked PVA matrix.