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U.r. and Raman spectra of glasses of composition $N{a}_{2}O\cdot x{B}_2{O}_3$ (x = 2, 3, 4, 5, 6 e 9) are reported. By comparison with known crystalline structure of borate and polyborate u.r. spectra, it is possible to reveal a gradual boron transformation from trigonal to tetrahedral coordination, when the NaO percentage in glass composition rises. The Raman spectra too support this behaviour, moreover we may characterize the presence of BO(O) rings in the glass structure by a typical band near 800 cm. Heating the materials...

Infrared spectra of the materials composing the $CaS{O}_4\cdot 2H_{2}O-CaS{O}_4$ system have been examined. $CaS{O}_4\cdot 2H_{2}O$ films laid down from a n-hexane suspension on KBr disks were heated to controlled temperatures in the atmosphere, under vacuum ($5\cdot {10}^{-2}$mmHg) and at the vapour pressure of 21 mmHg. Infrared spectra indicate that a direct transformation of $CaS{O}_4\cdot 2H_{2}O$ into anhydrous $CaS{O}_4$ occurs in a definite temperature interval, which depends on each case. Infrared spectra, recorded from $CaS{O}_4\cdot 2H_{2}O$ film heated under the vapour pressure of 140 mmHg, show, on the contrary,...