thermotropic mesophase 

https://doi.org/10.1351/goldbook.TT06897
A mesophase formed by heating a solid or cooling an isotropic liquid, or by heating or cooling a thermodynamically stable mesophase.
Source:
PAC, 2002, 74, 493. (Definitions of basic terms relating to polymer liquid crystals (IUPAC Recommendations 2001)) on page 496 [Terms] [Paper]