State of nondissociated molecules of water inclusions in aluminosilicate glasses (1H NMR and electron microscopy study)

Four species of nondissociated water inclusions observed in H 2 O bearing quartz and aluminosilicate glasses were experimentally studied by temperature solid state 1 H NMR. These inclusions are as follows: (1) Bubble water has the 1 H NMR spectrum as a singlet with a full width at half maximum (FWHM) ∼250 Hz. (2) Water macroclusters containing ∼10 3 H 2 O molecules form the 1 H NMR singlet with a FWHM∼500 Hz. The macrocluster water is the supercooled state down to ∼240 K and shows sharp hysteresis in the aggregate state. (3) Strongly H-bonded (SHB) water clusters are inclusions consisting of several (∼10) H 2 O molecules linked by strong hydrogen bonds. These indusions generate, in 1 H NMR spectrum, a wide line with a FWHM∼10 kHz which narrows sharply with 300 K and higher. (4) Single isolated H 2 O molecules are the smallest water inclusions. They are only observed in the multicomponent aluminosilicate glasses and are practically absent in pure quartz glasses. A phase state differs in the inclusions under study-the water in the bubbles and macroclusters is liquid but the water of structure clusters is quasi-solid. Isolated H 2 O molecules are a physical solution of water in glass.