Magic angle spinning nuclear magnetic resonance (MAS NMR) is used to measure the ~(29)Si chemical shift and full width at half maximum in Na_(2)O·2SiO_(2)·xMnO for 0.0≤x≤0.8 glasses. The large space varying magnetic field of the paramagnetic centers increases the line width and moves the chemical shift to a lower frequency, i.e. more shielded, with the increase of Mn~(++). The T_(1) relaxation time falls rapidly and the relaxation rate is shown to be proportional with the concentration of MnO. The differential thermal analysis (DTA) results show that the glass transition temperature, T_(g), crystallization temperature, T_(x), and liquidus temperature T_(L) do not change due to addition of MnO. This suggests that Mn~(++) does not form chemical bond with the network. However, the Mn~(++) acts as nucleating agent and enhances the crystallization and the rate of crystallization can be tailored by judicious choice of the amount of MnO.
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