Effect of OH-content on thermal and chemical properties of SnOP2O5 glasses

Glasses with 55–60 mol% SnO and 40–45 mol% 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 3000 nm with an absorption intensity >20 cm−1, bands at 2140 nm with intensity ∼5 cm−1, at 2038 nm with intensity ∼2.7 cm−1, and at 1564 nm with intensity ∼0.4 cm−1 were measured. These samples have shown a mass loss of 3–4 wt% 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 3150 nm and low absorption intensity <4 cm−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.