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The kinetics of the transformation of germanium oxide have been studied in the temperature range, 800-1200"C, by X-ray measurements. Germanium oxide, in the pure state, does not transform by heating up to 1000°C, but it does transform in the presence of a catalyst. The kinetic data can be fitted reasonably well by the first-order equation and the energy of activation obtained in the present study is about 100 kcal/mole. The transformation rate is significantly affected by the surrounding atmosphere.The results can be formally interpreted in terms of a model set forth by Avrami, and are compared with the results for silica and titanium oxide.

The role of alkali germanates as catalysts in the polymorphic transformation of germanium dioxide was investigated by high-temperature X-ray diffraction method. Lithium germanate and sodium germanate catalyze the transformation in a solid state, the activation energies being larger than 80 kcal/mol. Potassium germanate catalyst plays its role in a liquid state, the activation energy being smaller than that of other catalysts.

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The effect of surrounding atmosphere on the phase transformation of germanium dioxide with alkali germanate catalysts was investigated by high temperature X-ray diffraction method. The catalysts were Li2O·7GeO2, 3K2O·11GeO2, K2O·7GeO2 and 2Na2O·9GeO2. The ambient atmospheres were dry or wet nitrogen and oxygen. The effect of atmosphere was found to be not so large as that of the catalyst. Water vapor has prominent effects upon the transformation as in other solid state reactions.