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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>J.A. Philpotts</dc:contributor>
  <dc:contributor>D.W. Matson</dc:contributor>
  <dc:creator>S.K. Sharma</dc:creator>
  <dc:date>1985</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Raman spectra of crystalline polymorphs of a number of tectosilicate minerals having various sizes of smallest rings of TO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;tetrahedra (T = Si, Al) have been investigated to identify the bands that are sensitive indicators of the smallest rings in the network. The information obtained from the Raman spectra of tectosilicate minerals (e.g., SiO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;polymorphs, NaAlSi&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;O&lt;/span&gt;&lt;sub&gt;8&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(Ab), NaAlSiO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(Ne), KAlSi&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;span&gt;O&lt;/span&gt;&lt;sub&gt;8&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(Or), and KAlSi&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;O&lt;/span&gt;&lt;sub&gt;6&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(Lc)) is used to interpret the Raman spectra of the isochemical glasses. It is shown that the frequency of the dominant&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;s&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(TOT) band in the spectra of both crystals and glasses is related to the dominant size of TO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;rings in the structure. In agreement with previous X-ray RDF work, it is found that in the glasses of Ab and Jd (NaAlSi&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;O&lt;/span&gt;&lt;sub&gt;6&lt;/sub&gt;&lt;span&gt;) compositions, six-membered rings of TO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;tetrahedra predominate. The Raman spectrum of Or glass, however, indicates that clusters of intermixed four- and six-membered rings of TO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;tetrahedra, similar to those existing in crystalline leucite, are also present in the glass. Raman evidence indicates that four-membered rings of TO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;span&gt;&amp;nbsp;tetrahedra predominate in the glass of An composition. Similarly, the higher frequency of the&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;s&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(TOT) band in the spectrum of Ne glass as compared with the frequency the&amp;nbsp;&lt;/span&gt;&lt;i&gt;ν&lt;/i&gt;&lt;sub&gt;s&lt;/sub&gt;&lt;span&gt;&amp;nbsp;(TOT) band in the spectra of crystalline cargenieite and nephelite indicates either an admixture of the four- and six-membered rings or the puckering of six-membered rings in the glass structure.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0022-3093(85)90311-4</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Ring distributions in alkali- and alkaline-earth aluminosilicate framework glasses- A raman spectroscopic study</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>