This study aimed to investigate the influence of Na2O addition on the structural, thermal, and electrical characteristics of oxynitride glass-ceramics within the Na–K–Mg–Ca–Al–Si–O–N system. Oxynitride glass-ceramic samples were prepared via spark plasma sintering (SPS) with sodium oxide doping levels ranging from 0 wt% to 12 wt%. FESEM analysis revealed changes in sample morphology with increasing sodium content, indicating the...