ABSTRACT Ag 2 O‐doped ( x )RO–(54– x )ZnO–5Al 2 O 3 –40P 2 O 5 ( x = 5 or 10 mol%; R = Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ ) glasses were synthesized to probe how alkaline‐earth chemistry controls silver redox, nanoclustering, and network structure. UV–visible spectra showed a marked transmittance loss near 415 nm from the surface plasmon resonance (SPR) of metallic Ag, with SPR intensity rising from Mg → Ca → Sr → Ba, consistent with greater Ag + →Ag 0 reduction as the modifier field strength decreases. X‐Ray photoelectron spectroscopy indicated a larger Ag 0 fraction in Ba‐rich glasses. High‐resolution TEM on Ba‐doped samples revealed Ag 0 nanocrystallites (∼2–10 nm) with d‐spacings of 0.23 and 0.20 nm indexed to fcc‐Ag (111) and (200). Optical basicity and oxide‐ion polarizability estimates, together with FT‐IR/Raman, pointed to enhanced reduction and depolymerization with heavier alkaline earths. Correspondingly, 31 P and 27 Al MAS NMR showed more non‐bridging oxygen in Ba 2+ glasses and a shift of Zn and Al toward higher coordination, decreasing charge‐compensation sites. Overall, lower‐field‐strength, higher‐basicity modifiers increase network ionicity and NBO content, promoting silver reduction and nanocluster growth, whereas Mg 2+ suppresses these processes and preserves optical transparency.
Cho et al. (2026) studied this question.