Raman, Brillouin, and nuclear magnetic resonance spectroscopic studies on shocked borosilicate glass
Raman, Brillouin, and nuclear magnetic resonance spectroscopic studies on shocked borosilicate glass
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DOI：
10.1063/1.3592346
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发表时间：
2011-06-01
影响因子：
3.2
通讯作者：
Williams, Quentin
中科院分区：
文献类型：
--
作者：
Manghnani, Murli H.;Hushur, Anwar;Williams, Quentin
使用布里渊和拉曼散射和NMR技术，我们已经研究了四个后冲击试样的硼硅酸盐玻璃，恢复从峰值压力为19.8，31.3，40.3，和49.1 GPa的弹性和结构特性。冲击波压缩硼硅酸盐玻璃的拉曼光谱在峰值压力为19.8和31.3 GPa时显示出两个新的峰，位于606 cm（-1）和1600 cm（-1）附近，而在冲击加载后，这些玻璃中的一个类似于923 cm（-1）的峰消失了。在606 cm（-1）处的模式与四元环相关，由一个BO（4）和三个SiO（4）四面体组成（一种类似于里德汞铀矿的构型）。与1600 cm（-1）相近的模式起源不明，而在923 cm（-1）处的模式可能与具有两个非桥氧的二氧化硅四面体有关，尽管这类玻璃的标准模型表明总的非桥氧含量应该很低。冲击样品在40.3和49.1 GPa的拉曼光谱与未冲击样品的相似，这表明大部分不可逆的密度和结构变化在绝热减压和热弛豫后是可恢复的。最高压力冲击样品的这种可逆性与布里渊散射结果雅阁，布里渊散射结果显示在高达20 GPa的压力下声速和折射率的乘积增加。最初在450 cm（-1）处的拉曼谱带对应于Si-O-Si，Si-O-B（网络中主要是六元环）的弯曲振动模式，达到470 cm（-1）的最大频率，并在峰值冲击压力为31.3 GPa时变窄，然后也降低到其初始值（对于在40.3和49.1 GPa冲击的样品）。在冲击波压缩下向更高频率的这种偏移表明平均Si-O-Si、Si-O-B角随压力减小。该带的变窄表明在峰值压力为19.8和31.3 GPa的冲击样品中Si-O-Si角的分布更窄。(11)B所有四种冲击玻璃的NMR光谱是相似的，并且表明BO（3）与BO（4）的比率与起始材料相比没有很大变化。然而，峰形的变化表明网络中B和Si组分的连接性发生了显著变化，在冲击玻璃中，BO（4）四面体周围有更多的硅邻居，冲击加载后非环相关BO（3）基团的数量略有增加。因此，冲击载荷的不可逆效应似乎是产生更小的四面体环（因此降低了平均T-O-T键角），并增加了硼四面体周围Si邻居的平均数量。(C)2011年美国物理学会。[doi：10.1063/1.3592346]
Using Brillouin and Raman scattering and NMR techniques, we have investigated the elastic and structural properties of four post-shocked specimens of borosilicate glass, recovered from peak pressures of 19.8, 31.3, 40.3, and 49.1 GPa. The Raman spectra of shock-wave compressed borosilicate glass for peak pressures of 19.8 and 31.3 GPa show two new peaks at 606 cm(-1) and near 1600 cm(-1), while a peak at similar to 923 cm(-1) disappears in these glasses following shock-loading. The mode at 606 cm(-1) is correlated with four-membered rings, composed of one BO(4) and three SiO(4) tetrahedra (a reedmergneritelike configuration). Modes near similar to 1600 cm(-1) are of uncertain origin, while that at 923 cm(-1) may associated with silica tetrahedra with two nonbridging oxygens, although standard models of this type of glass suggest that total nonbridging oxygen contents should be low. The Raman spectra for the shocked samples at 40.3 and 49.1 GPa are similar to that of the unshocked sample, suggesting that much of the irreversible density and structural changes are recoverable following adiabatic decompression and thermal relaxation. This reversibility for the highest pressure shocked samples is in accord with the Brillouin results, which show an increase in the product of sound velocity and index of refraction at pressures up to 20 GPa. The Raman band initially at 450 cm(-1), which corresponds to the bending vibration mode of the Si-O-Si, Si-O-B (with primarily six-membered rings in the network) reaches a maximum frequency of 470 cm(-1) and narrowing at a peak shock pressure of 31.3 GPa, and then also decreases to its initial values for samples shocked at 40.3 and 49.1 GPa. This shift toward higher frequency under shock-wave compression indicates the average Si-O-Si, Si-O-B angles decrease with pressure. The narrowing of this band suggests a narrower distribution of Si-O-Si angles in the shocked samples for peak pressures of 19.8 and 31.3 GPa. (11)B NMR spectra for all four shocked glasses are similar, and indicate ratios of BO(3) to BO(4) that are not greatly changed from the starting material. However, changes in peak shapes suggest significant changes in the connectivity of the B and Si components of the network, with more silicon neighbors surrounding BO(4) tetrahedra in the shocked glasses, and a modest increase in the number of nonring related BO(3) groups following shock-loading. Thus, the irreversible effects of shock-loading appear to be to generate smaller rings of tetrahedra (hence decreasing the average T-O-T bond angle), and to increase the average number of neighbors of Si around boron tetrahedra. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3592346]