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Science 25 April 2003:
Vol. 300. no. 5619, pp. 619 - 622
DOI: 10.1126/science.1082364
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Reports

The Glass-to-Glass Transition and Its End Point in a Copolymer Micellar System

Sow-Hsin Chen,1* Wei-Ren Chen,1 Francesco Mallamace2

We present experimental evidence, obtained from small-angle neutron scattering and photon correlation measurements, indicating the existence of two types of structurally arrested (glassy) states in a copolymer micellar system with a short-range interparticle attractive interaction. Within a certain range of micellar volume fractions, a sharp transition between these two types of glass is observed by varying the temperature. Furthermore, we found an end point of this transition line beyond which the two glasses become identical in their local structure and their long-time dynamics. These findings confirm the recent mode-coupling theory predictions regarding the phase behavior of the structurally arrested states for this type of system.

1 Department of Nuclear Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
2 Dipartmento di Fisca e Instituto Nazionale per la Fisica della Materia, Universita' di Messina, I-98100 Messina, Italy.

* To whom correspondence should be addressed. E-mail: sowhsin{at}mit.edu

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Science. ISSN 0036-8075 (print), 1095-9203 (online)