Yes, according to the writing norms of chemistry and materials science, the glass transition temperature (Tg) is usually expressed in italics. This is because Tg is a physical quantity, not a conventional word or symbol. The use of italics can make Tg more prominent in the text, easy to identify, and avoid confusion with other conventional texts.

In addition, the use of italics can also show that Tg is a symbol, not an ordinary word. This is very important in scientific papers, because it can help readers better understand the author's intention and expression. Therefore, in writing, we should always follow the writing norms of scientific papers and use correct formats and marks to represent various physical quantities and symbols.

In short, the glass transition temperature (Tg) should be expressed in italics, which is the requirement of writing norms in the fields of chemistry and materials science. When writing, we should pay attention to the accuracy of details and marks, follow academic norms, and ensure the quality and readability of articles.