Corrigendum to "Synthesis of bulk silicon oxynitride glass through nitridation of SiO2 aerogels and determination of Tg". Issue 1 (30th August 2021) - Osawa, Yuta; Iwasaki, Kenichiro; Nakanishi, Takayuki; Yasumori, Atsuo; Matsui, Yoshio; Nishimura, Toshiyuki; Ohsawa, Takeo; Segawa, Hiroyo; Ohashi, Naoki