Intermediate Phase Spectroscopy of (Na$_{\mathrm{2}}$O)$_{\mathrm{x}}$[(B$_{\mathrm{2}}$O$_{\mathrm{3}})_{\mathrm{y}}$(GeO$_{\mathrm{2}})_{\mathrm{1-y}}$]$_{\mathrm{1-x}}$ glasses

The titled ternary is of interest because the two end members, viz., y$=$ 0, i.e., Sodium Germanate $^{\mathrm{1}}$, and y $=$ 1, Sodium Borate $^{\mathrm{2}}$ have been studied earlier and show the isostatically rigid Intermediate Phase (IP) to occur in the x $=$ 0.14 to x $=$ 0.19 range and in the x $=$ 0.20 to x $=$ 0.40 range of soda respectively. In the present work we now report on bulk glasses at y $=$ 0.75 synthesized over a wide range x $=$ 0 to x $=$ 0.30 of soda. Our motivation is to understanding the evolution of the IP in the pseudo-ternary glasses as the base glass connectivity is altered. Preliminary MDSC experiments show T$_{\mathrm{g}}$(x) to increase with x and to reveal a broad maximum at 510 C centered near x $=$ 0.25. Furthermore, an IP is found in the x $=$ 0.20 to x $=$ 0.33 range of soda where a reversibility window is observed. The window is centered near the T$_{\mathrm{g}}^{\mathrm{max}}$ content at x$=$ 0.25. IR reflectance show modes of BO$_{\mathrm{4}}$ and BO$_{\mathrm{3}}$ units but also those of bonded water. Raman scattering largely shows modes observed earlier in Sodium borate glasses$^{\mathrm{2}}$. 1 V. Rompicharla et al. J PCM 20, 202101 (2008) 2K. Vignarooban et al. EPL 108, 56001(2014).