<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31311765</termId><termName>photochromism</termName><termType>PT</termType><termNote><![CDATA[ Describes a phenomenon of photosensitivity in which a material undergoes a change of color when illuminated with light of the appropriate wavelength; and reverts to its original state either in the dark or upon treatment with irradiation of a different wavelength.  ]]></termNote><termCreatedDate>2026-03-30 20:24:00</termCreatedDate><relation><relationType>UF</relationType><termId>31311766</termId><termName>photochromic</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31301538</termId><termName>photosensitivity</termName><termType>PT</termType></relation></term>  </Zthes>