EN
The structural effects of yttrium (Y) and cerium
(Ce) are investigated when substituted for sodium (Na) in
a 0.52SiO2–0.24SrO–(0.24−x)Na2O–xMO (where x = 0.08;
MO = Y2O3 and CeO2) glass series. Network connectivity
(NC) was calculated assuming both Y and Ce can act as
a network modifier (NC = 2.2) or as a network former (NC
up to 2.9). Thermal analysis showed an increase in glass
transition temperature (Tg) with increasing Y and Ce content,
Y causing the greater increase from the control (Con)
at 493∘C to 8 mol% Y (HY) at 660∘C. Vickers hardness (HV)
was not significantly different between glasses. 29Si Magic
Angle Spinning-Nuclear Magnetic Resonance (MAS-NMR)
did not show peak shift with addition of Y, however Ce
produced peak broadening and a negative shift in ppm.
The addition of 4 mol% Ce in the YCe and LCe glasses
shifted the peak from Con at −81.3 ppm to −82.8 ppm and
−82.7 ppm respectively; while the HCe glass produced a
much broader peak and a shift to −84.8 ppm. High resolution
X-ray Photoelectron Spectroscopy for the O 1s spectral
line showed the ratio of bridging (BO) to non-bridging oxygens
(NBO), BO:NBO,was altered,where Con had a ratio of
0.7, HY decreased to 0.4 and HCe to 0.5.