Angelo V. Santoro

Vibrational Spectra of Liquid Crystals. I. Changes in the Infrared Spectrum at the Crystal–Nematic Transition

The infrared spectra of 4,4′‐bis(alkoxy) azoxybenzenes (methyl, ethyl, butyl, pentyl, and hexyl) have been examined as a function of temperature through the crystal–nematic transition. Several bands are observed to disappear gradually as this transition is approached. The nature of these vibrational modes and the relative rates of their disappearance are discussed in terms of a lattice defect model of the crystal–nematic transition. Preliminary results for the crystal–smectic transition in 4,4′bis(heptyloxy) azoxybenzene are also reported.

Differential Thermal Analysis of Rapid High Pressure Decompositions

Abstract A simple sample handling technique for recording differential thermograms of volatile and/or high pressure producing compounds is described. The calculation of activation energies for several hydrazines and explosives is reported.

Differential thermal analysis with capillary tubes

ZusammenfassungEin Verfahren zur Durchführung von Differential-Thermoanalysen in verschlossenen Kapillarröhrchen wurde beschrieben, womit Aktivierungsenergien und andere kinetische Daten für thermisch induzierte Reaktionen ermittelt werden künnen. Proben von 2 bis 4 mg werden verwendet. Die Ergebnisse entsprechen denen, die mit dem kürzlich beschriebenen Makrosystem ermittelt wurden.