Thermochromic, fluorescent fluid
While thermochromicity already was known for me, for example as thermometer for fish tanks like here, a search based on "thermochromic fluorescent fluid" as keyword yielded this video.

Beside safety, yet indeed, it is easier to fill the sculptures with a liquid / a solution of a fluorescent dye excited by black light from the inner of the (glass) sculpture and to wrap the container with thermochromic dyes. These are even commercialized as here and here.  "Black light" is an other name for ultraviolett light, and there are even hand-size battery powered lamps found in the chemistry lab, or in civil life to check banknotes.

Disclaimer: I have no relationships to the said corporation.

Addendum:  Examples of fluorescence triggered solely by the gentle warmth of a hand are not known to me (yet).