Department or Program



Four compositions along the nepheline-kalsilite join and four along the jadeite-leucite join were synthesized in order to test the effects of the Na:K ratio on melt viscosity and heat capacity within the SiO2-NaAlSiO4-KAlSiO4 system. Na:K ratios include [100:0], [75:25], [50:50], and [25:75]. Chemical compositions of each glass were determined using an electron microprobe. Compositions along the Jd-Lct join consist of 65 mol % SiO2 and 17 mol % Al2O3. Compositions along the Ne-Kls join consist of 48 mol % SiO2 and 26 mol % Al2O3. A parallel plate viscometer was used to measure viscosities between 804°C and 991°C, and a concentric cylinder viscometer was used to measure viscosities between 1409°C and 1588°C. Between 804°C and 991°C, Ne25Kls75 is approximately 0.5-1 log units more viscous than Ne50Kls50. Between 1409°C and 1588°C, compositions along the Ne-Kls join increase in viscosity with increasing mole fraction K. Using TVF parameters, log viscosity of each composition was calculated at 1200K and plotted against mole fraction K. Results indicate a deviation from linear behavior for both Ne-Kls and Jd-Lct compositions with alkali mixing. Therefore, this study reflects the alkali mixing effect on alkali-rich, silica-undersaturated aluminosilicate melts.

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Restricted: Campus/Bates Community Only Access

First Advisor

Genevieve Robert

Date of Graduation


Degree Name

Bachelor of Science

Number of Pages


Components of Thesis

1 pdf file


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