In this paper, the influence of the stabilization temperature on the bonding configuration and the structural and textural prop-erties of sol–gel glasses in the SiO 2 –P 2 O 5 –CaO system is pre-sented. Raman and infrared spectroscopy are used for detecting and quantifying the local changes in the glass structural sym-metry. It is demonstrated that the heat treatment leads to a re-polymerization of the glass structure through condensation reactions, inducing configurational transitions from reactive chains to the more stable condensed rings. Moreover, high-res-olution transmission electron microscopy analysis reveals the presence of nanocrystalline areas associated with orthophos-phate groups, presenting different features depending on the stabilization temperature.