I.Teslyuk, Yu. Nastishin and R.Vlokh
Polarization microscopy observations of the lysozyme single crystals in the 4C–40C region are represented. The interference colours of the crystal texture observed between crossed polarizers drastically change at TC=11C unambiguously displaying a phase transition. The temperature dependence of the birefringence deduced from these observations indicates that the phase transition is of strongly first order. The low-temperature (T<11 C) phase intensively scatters light. The phase transition is accompanied by the deformation (about 5%) of the crystal. The observed textural changes are reversible in temperature. We argue that the phase transition is of a ferroelastic type and the low-temperature (T<11C) phase might be of a ferroelastic type with symmetry 222 or one of two ferroelectric-ferroelastic types of symmetries 2 or 1.
PACS: 78.20.Fm, 77.84, 64.70.Kb
Key words: biocrystals, lysozyme, phase transition, ferroelasticity,
optical birefringence
doi 10.3116/16091833/5/4/118/2004
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