document updated a month ago, on Jan 9, 2025
thermochromic materials that can survive 500° F
- this Wikipedia article says "Temperatures above about 200–230 °C (392–446 °F) typically cause irreversible damage to leuco dyes"
- Also, "Chromium(III) oxide and aluminium(III) oxide in a 1:9 ratio is red at room temperature and grey at 400 °C"