We　have　prepared　twelve　Ge-As-Se　chalcogenide　glass　films　with　different　chemical　compositions　and　investigated　their　stability　to　exposure　with　near　bandedge　light.　The　evolution　of　two　key　parameters,　the　refractive　index　at　1550　nm　and　the　bandgap　with　increasing　fluence　were　fitted　with　stretched-exponential　functions.　While　most　of　the　films　showed　photo-bleaching　(or　photodarkening)　behavior,　we　found　that　for　films　with　a　mean　coordination　number　(MCN)　around　a　parts　per　thousand　2.45-2.50,　neither　the　bandgap　nor　the　refractive　index　changed　upon　irradiation,　demonstrating　that　photostable　glasses　exist　with　a　particular　chemical　composition　corresponding　to　the　strongest　glass　formers.　Such　photostable　glasses　are　the　best　choice　for　applications　in　photonics.