In this study we have evaluated the concentration of defect centers like voids, their size (up to nanoscale) and the fraction of free volume space integrated in Li₂SO₄−MgO−P₂O₅:NiO glass system as a function of NiO content. Positron annihilation lifetime (PAL) technique with ²²Na positron source of radio activity 100 kBq is used for this study. The size, shape and the concentration of entrenched defects in the glass matrix are predicted to influence profoundly the physical properties of the glass. Cavity radius (R) and the entrenched free volume fraction (f_v) are found to be the maximal in the sample doped with 0.8 mol% of NiO. This observation suggested that Ni²⁺ ions predominantly occupied octahedral positions (acted as modifiers along with SO₄^2– ions) and induced large concentration of structural defects. The obtained information is found to be in concurrent with inferences drawn from dielectrics and spectroscopic studies of these glasses reported earlier.

在这项研究中，我们评估了缺陷中心（如空隙）的浓度，其大小（至纳米级）以及整合在Li ₂ SO ₄ -MgO-P ₂ O ₅：NiO玻璃系统中的自由体积空间分数（随NiO的变化）内容。本研究使用正电子an灭寿命（PAL）技术和²² Na正电子放射源100 kBq。预计玻璃基质中的缺陷的大小，形状和浓度会深刻影响玻璃的物理性能。发现在掺杂有0.8 mol％NiO的样品中，腔半径（R）和固定的自由体积分数（f _v）最大。该观察结果表明Ni ²⁺离子主要占据八面体位置（与SO ₄ ^2-离子一起用作改性剂），并引起大量的结构缺陷。发现获得的信息与从较早报道的这些玻璃的介电和光谱研究得出的推论同时进行。