TT #677 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:05
When brothers dwell together and one of them dies and has no son, the wife of the dead shall not be outside to a strange man; her husband’s brother shall come upon her and take her to himself as a wife and perform the duty of a husband’s brother for her.
Torah Temimah points to Yevamot 39a.
TT lemma: וּלְקָחָהּ לוֹ לְאִשָּׁה.
הַכּוֹנֵס אֶת יְבִמְתּוֹ הֲרֵי הִיא כְּאִשְׁתּוֹ לְכָל דָּבָר וּמְגָרְשָׁהּ בְּגֵט וּמַחֲזִירָהּ, דַּאֲמַר קְרָא וּלְקָחָהּ לוֹ לְאִשָּׁה.
English: One who takes his yevamah — she becomes his wife in every respect; he divorces her with a get and may remarry her, for Scripture says “and he shall take her to himself as a wife.”
On the daf / in context: After yibbum the relationship is a full marriage; the prior zikah does not leave residual prohibitions.
Derash on full marital status after yibbum.
Once yibbum is performed the woman is a full wife for all purposes, including divorce by get and the possibility of remarriage.