Mixed modifier effect in lithium‐calcium borosilicate glasses. Issue 12 (26th July 2017)

• Record Type: Journal Article
• Authors: Shih, Yueh‐Ting; Jean, Jau‐Ho
• Is Part Of: Journal of the American Ceramic Society. Volume 100:Issue 12(2017)
• Page Start: 5482
• Page End: 5489
• Publication Date: 2017-07-26
• Subjects: borosilicate glass -- mixed modifier effect -- network -- transport‐related properties; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.15059
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: The mixed modifier effect (MME) in the lithium‐calcium borosilicate glasses, which have a composition of 0.4[(1− x )Li2 O– x CaO]–0.6[(1− y )B2 O3 – y SiO2 ] with x in the range of 0~1 and y in the range of 0.33~0.83, is investigated. The MME manifests itself as a positive deviation from linearity in the activation energy of electrical conductivity (Ea σ ) and as a negative deviation from linearity in the fraction of four‐coordinated boron ( N 4 ), glass transition temperature ( T g ), dilatometric softening temperature ( T d ), Vickers microhardness (Hv ), dielectric constant (ε), and dielectric loss (tanδ). Moreover, the deviation, which exhibits a maximum at [CaO]/([CaO]+[Li2 O])=0.5, is enhanced with increasing [SiO2 ]/[B2 O3 ] ratio in the glass network. The observed MME in T g, T d, and Hv are attributed to the bond weakening in the network; however, the MME in ε, tanδ, and Ea σ are caused by the obstruction of modifier transport in the glass network.