Effect of OH-content on thermal and chemical properties of SnO[sbnd]P2O5 glasses

Abstract

Glasses with 55–60mol% SnO and 40–45mol% P2O5 have shown extremely large differences in the chemical and thermal properties depending on the temperature at which they were melted. Glasses prepared at low melting temperature, 450–550°C, had low Tg, 150–200°C, and low chemical stability. Glasses prepared at high melting temperature, 800–1200°C, had much higher Tg, 250–300°C, and much higher chemical stability. No significant differences were found by 119Sn Mössbauer and 31P Nuclear Magnetic Resonance spectroscopy. Large differences in the OH-content could be detected as the reason by infrared absorption spectroscopy, thermal analyses, and 1H Nuclear Magnetic Resonance spectroscopy. In samples with low Tg, a broad OH – vibration band around 3000nm with an absorption intensity >20cm−1, bands at 2140nm with intensity ∼5cm−1, at 2038nm with intensity ∼2.7cm−1, and at 1564nm with intensity ∼0.4cm−1 were measured. These samples have shown a mass loss of 3–4wt% by thermal gravimetric analyses under argon in the temperature range 400–1000°C. No mass loss and only one broad OH-band with a maximum at 3150nm and low absorption intensity <4cm−1 could be detected in samples melted at high temperature, 1000–1200°C, which have much higher Tg, ∼300°C, and much higher chemical stability.