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Do glass beads show any piezoelectric property? Since glass beads are mostly made out of SiO2 which is piezoelectric, will it show any piezoelectric property?

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No, glass and indeed all amorphous materials do not exhibit piezoelectricity because piezoelectricity is intimately connected to the crystal structure of the material. Roughly speaking, if the charges within the unit cell are asymetrically distributed then when the crystal is mechanically deformed the positive and negative charges may be displaced by differing amounts. This creates an electric polarization within the crystal.

The symmetry of the crystal unit cell is described by the point group, and only crystals with non-centrosymmetric can exhibit piezoelectricity. The point group of quartz is 32 and this is non-centrosymmetric. Being amorphous, silica has no point group but on average it is centrosymmetric so it cannot exhibit piezoelectricity.

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  • $\begingroup$ Your argument with centrosymmetric unit cells is correct but limited to single crystals. There are amorphous materials, such as PVDF, a plastic material, that are piezoelectric. You only need on average a net polarization which can be achieved even in amorphous materials. $\endgroup$ – Alexander Nov 21 '13 at 11:28
  • $\begingroup$ Yes, OK, but PVDF has some long range order because it's stretched to align the polymer chains. So it's not amorphous in the sense that glass is. $\endgroup$ – John Rennie Nov 21 '13 at 11:39
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The issue is that for a piezoelectric material you need a common orientation of the dipole moments. In normal glass there is no preferred direction and therefore an electric field will not create a bulk change in length.

On the other hand it is possible to manufacture a piezoelectric glass, e.g. from a compound related to strontium titanate (link to journal article) by orienting the molecular dipoles during the glass transition. This might be possible for SiO$_2$ as well but is not the case for glass beads that have not undergone any special treatment.

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