Kurita Rei, Tanaka Hajime
Institute of Industrial Science, University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan.
Phys Rev Lett. 2005 Aug 5;95(6):065701. doi: 10.1103/PhysRevLett.95.065701. Epub 2005 Aug 4.
When a liquid approaches its glass-transition temperatures T(g), the structural relaxation time tau dramatically increases. This basic feature is ubiquitous, but this increase of tau can be classified between strong and fragile extremes using T(g) as a scaling parameter. Liquids, whose tau obeys the Arrhenius law, are called "strong," while "fragile" liquids have the super-Arrhenius behavior. Here we report the first continuous control of the fragility of liquid of the same material over a wide range of fragility, using a continuous liquid-liquid transition. Our study clearly demonstrates that the fragility is not a material-specific quantity, but is controlled by the order parameter governing the liquid-liquid transition, which may be the fraction of locally favored structures in the liquid.
当一种液体接近其玻璃化转变温度T(g)时，结构弛豫时间tau会急剧增加。这一基本特征普遍存在，但tau的这种增加可以根据T(g)作为标度参数在强和弱极端情况之间进行分类。tau遵循阿仑尼乌斯定律的液体被称为“强”液体，而“弱”液体具有超阿仑尼乌斯行为。在此，我们报告了通过连续的液-液转变，首次在很宽的脆弱性范围内对同一种材料的液体脆弱性进行连续控制。我们的研究清楚地表明，脆弱性不是一个材料特有的量，而是由控制液-液转变的序参量所控制，该序参量可能是液体中局部有利结构的比例。
