Karmakar, Basudeb and Kundu, Paritosh and Chaudhuri, A K and Annapurna, K and Kumar, A and Dwivedi, Ravindra Nath (1999) Effect of hydroxyl content on the physical properties of calcium metaphosphate glasses. Bulletin of Materials Science, 22 (2). pp. 115-119. ISSN 0250-4707

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Abstract

The hydroxyl (OH) content of calcium metaphosphate glasses has been controlled in the range 50-800 ppm by melting calcium dihydrogen phosphate in air, under vacuum and with fluoride addition. Density, refractive index and glass transition temperature of the glasses increase with decrease in OH content while the coefficient of thermal expansion remains almost unchanged. With gradual decrease in OH, the UV cutoff initially shifts towards shorter and finally towards longer wavelengths. IR spectroscopic study shows that the OH groups exist exclusively in the hydrogen bonded states, Correlations of the glass properties with OH content have been explained in terms of structural rearrangement leading to the change in P-O bond length and O-P-O/P-O-P bond angles of the PO4 tetrahedral units of (PO3-)(n) chains. These changes are caused due to conversion of non-bridging oxygens (NBOs) of the H-bonded OH groups into bridging oxygens (BOs) during progress of dehydroxylation.

Item Type:	Article
Uncontrolled Keywords:	Phosphate glass; Hydroxyl content; Glass properties; IR spectra; hydrogen bond
Subjects:	Glass
Divisions:	Glass
Depositing User:	Bidhan Chaudhuri
Date Deposited:	19 Jun 2012 08:00
Last Modified:	26 Feb 2016 05:37
URI:	http://cgcri.csircentral.net/id/eprint/1504

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