The symbolism of the glass menagerie changes to parallel the changes in Laura. Laura herself is symbolized by her glass collection, as she is both beautiful and fragile. Like her glass pieces, Laura "shines" when the light of love or attention falls upon her. Of all her pieces, the unicorn symbolizes her most fully; like the unicorn, Laura is unique and not of the real world. At the play's conclusion, the unicorn's horn is broken, making it less exotic and unusual, just as Laura has been drawn momentarily into the real world by Jim O'Connor. By the end, the glass menagerie still symbolizes Laura, but with a new dimension. She is still beautiful and fragile, but like her collection, she is no longer inviolate. The damaged unicorn has been given to Jim, breaking up the collection of animals, just as Laura's emotional withdrawal (and her sense of self) has been broken by Jim's selfish behavior.
The glass collection also symbolizes escape, as do the father's records and the apartment's fire escape. Before Jim's arrival, Laura can lose herself in her glass and escape from the realities of her own life and circumstances. After Jim's visit, however, this escape will be denied her. In the future, looking at her glass figures and remembering the unicorn that used to be among them will remind her of Jim.
The basic symbolism of the glass menagerie does not change, as the glass collection consistently relates to Laura throughout the play, but the symbolism itself is dynamic, reflecting the changes that occur in her heart and in her circumstances.